321651616 has 72 divisors (see below), whose sum is σ = 748185984. Its totient is φ = 134933760.

The previous prime is 321651599. The next prime is 321651637. The reversal of 321651616 is 616156123.

It is a super-2 number, since 2×321651616² = 206919524150822912, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 56785 + ... + 62191.

It is an arithmetic number, because the mean of its divisors is an integer number (10391472).

Almost surely, 2^321651616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 321651616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (374092992).

321651616 is an abundant number, since it is smaller than the sum of its proper divisors (426534368).

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

321651616 is a wasteful number, since it uses less digits than its factorization.

321651616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5454 (or 5433 counting only the distinct ones).

The product of its digits is 6480, while the sum is 31.

The square root of 321651616 is about 17934.6484771796. The cubic root of 321651616 is about 685.1651197662.

The spelling of 321651616 in words is "three hundred twenty-one million, six hundred fifty-one thousand, six hundred sixteen".