1221623800 has 48 divisors (see below), whose sum is σ = 2851446960. Its totient is φ = 486727680.

The previous prime is 1221623773. The next prime is 1221623803. The reversal of 1221623800 is 83261221.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221623803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39517 + ... + 63283.

It is an arithmetic number, because the mean of its divisors is an integer number (59405145).

Almost surely, 2^1221623800 is an apocalyptic number.

1221623800 is a gapful number since it is divisible by the number (10) 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 1221623800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1425723480).

1221623800 is an abundant number, since it is smaller than the sum of its proper divisors (1629823160).

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

1221623800 is a wasteful number, since it uses less digits than its factorization.

1221623800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24040 (or 24031 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 1221623800 is about 34951.7352931153. The cubic root of 1221623800 is about 1069.0035851646.

The spelling of 1221623800 in words is "one billion, two hundred twenty-one million, six hundred twenty-three thousand, eight hundred".