1657139440 has 40 divisors (see below), whose sum is σ = 4203110448. Its totient is φ = 602595840.

The previous prime is 1657139423. The next prime is 1657139483. The reversal of 1657139440 is 449317561.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×1657139440² = 5492222247207027200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 1657139393 and 1657139402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 940677 + ... + 942436.

Almost surely, 2^1657139440 is an apocalyptic number.

1657139440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1657139440 is an abundant number, since it is smaller than the sum of its proper divisors (2545971008).

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

1657139440 is a wasteful number, since it uses less digits than its factorization.

1657139440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1883137 (or 1883131 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 1657139440 is about 40707.9775965351. The cubic root of 1657139440 is about 1183.3676278275.

The spelling of 1657139440 in words is "one billion, six hundred fifty-seven million, one hundred thirty-nine thousand, four hundred forty".