1657312921 has 12 divisors (see below), whose sum is σ = 1831237632. Its totient is φ = 1498739000.

The previous prime is 1657312903. The next prime is 1657312931. The reversal of 1657312921 is 1292137561.

It is not a de Polignac number, because 1657312921 - 2¹¹ = 1657310873 is a prime.

It is a super-2 number, since 2×1657312921² = 5493372236227104482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1657312901) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12745 + ... + 58966.

It is an arithmetic number, because the mean of its divisors is an integer number (152603136).

Almost surely, 2^1657312921 is an apocalyptic number.

1657312921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1657312921 is a deficient number, since it is larger than the sum of its proper divisors (173924711).

1657312921 is a wasteful number, since it uses less digits than its factorization.

1657312921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71924 (or 71913 counting only the distinct ones).

The product of its digits is 22680, while the sum is 37.

The square root of 1657312921 is about 40710.1083393302. The cubic root of 1657312921 is about 1183.4089207992.

The spelling of 1657312921 in words is "one billion, six hundred fifty-seven million, three hundred twelve thousand, nine hundred twenty-one".