1221956532 has 72 divisors (see below), whose sum is σ = 3275181000. Its totient is φ = 382814208.

The previous prime is 1221956531. The next prime is 1221956569. The reversal of 1221956532 is 2356591221.

It is a happy number.

1221956532 is a `hidden beast` number, since 12 + 21 + 95 + 6 + 532 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 419594256 + 802362276 = 20484^2 + 28326^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221956531) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 788094 + ... + 789642.

It is an arithmetic number, because the mean of its divisors is an integer number (45488625).

Almost surely, 2^1221956532 is an apocalyptic number.

1221956532 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221956532, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1637590500).

1221956532 is an abundant number, since it is smaller than the sum of its proper divisors (2053224468).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221956532 is a wasteful number, since it uses less digits than its factorization.

1221956532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2865 (or 2860 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 1221956532 is about 34956.4948471668. The cubic root of 1221956532 is about 1069.1006307015.

The spelling of 1221956532 in words is "one billion, two hundred twenty-one million, nine hundred fifty-six thousand, five hundred thirty-two".