1557421497 has 12 divisors (see below), whose sum is σ = 2251738944. Its totient is φ = 1037297880.

The previous prime is 1557421477. The next prime is 1557421529. The reversal of 1557421497 is 7941247551.

1557421497 is a `hidden beast` number, since 1 + 557 + 4 + 2 + 1 + 4 + 97 = 666.

It is not a de Polignac number, because 1557421497 - 2⁶ = 1557421433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1557421477) 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, 71829 + ... + 90962.

It is an arithmetic number, because the mean of its divisors is an integer number (187644912).

Almost surely, 2^1557421497 is an apocalyptic number.

It is an amenable number.

1557421497 is a deficient number, since it is larger than the sum of its proper divisors (694317447).

1557421497 is a wasteful number, since it uses less digits than its factorization.

1557421497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163860 (or 163857 counting only the distinct ones).

The product of its digits is 352800, while the sum is 45.

The square root of 1557421497 is about 39464.1799230644. The cubic root of 1557421497 is about 1159.1386533304.

The spelling of 1557421497 in words is "one billion, five hundred fifty-seven million, four hundred twenty-one thousand, four hundred ninety-seven".