921680648640 has 784 divisors, whose sum is σ = 3451503310848. Its totient is φ = 233878689792.

The previous prime is 921680648633. The next prime is 921680648653. The reversal of 921680648640 is 46846086129.

It is a super-2 number, since 2×921680648640² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 1518419217 + ... + 1518419823.

Almost surely, 2^921680648640 is an apocalyptic number.

921680648640 is a gapful number since it is divisible by the number (90) 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 921680648640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1725751655424).

921680648640 is an abundant number, since it is smaller than the sum of its proper divisors (2529822662208).

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

921680648640 is a wasteful number, since it uses less digits than its factorization.

921680648640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 948 (or 923 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 54.

The spelling of 921680648640 in words is "nine hundred twenty-one billion, six hundred eighty million, six hundred forty-eight thousand, six hundred forty".