1221646692 has 72 divisors (see below), whose sum is σ = 3374128576. Its totient is φ = 336986496.

The previous prime is 1221646691. The next prime is 1221646693. The reversal of 1221646692 is 2966461221.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1221646691) and next prime (1221646693).

It is a self number, because there is not a number n which added to its sum of digits gives 1221646692.

It is not an unprimeable number, because it can be changed into a prime (1221646691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 61998 + ... + 79290.

Almost surely, 2^1221646692 is an apocalyptic number.

1221646692 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 1221646692, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1687064288).

1221646692 is an abundant number, since it is smaller than the sum of its proper divisors (2152481884).

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

1221646692 is a wasteful number, since it uses less digits than its factorization.

1221646692 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17365 (or 17334 counting only the distinct ones).

The product of its digits is 62208, while the sum is 39.

The square root of 1221646692 is about 34952.0627717450. The cubic root of 1221646692 is about 1069.0102624732.

The spelling of 1221646692 in words is "one billion, two hundred twenty-one million, six hundred forty-six thousand, six hundred ninety-two".