642157557 has 16 divisors (see below), whose sum is σ = 867652800. Its totient is φ = 422410752.

The previous prime is 642157531. The next prime is 642157559. The reversal of 642157557 is 755751246.

It is a happy number.

It is not a de Polignac number, because 642157557 - 2⁷ = 642157429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642157559) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 98398 + ... + 104720.

It is an arithmetic number, because the mean of its divisors is an integer number (54228300).

Almost surely, 2^642157557 is an apocalyptic number.

It is an amenable number.

642157557 is a deficient number, since it is larger than the sum of its proper divisors (225495243).

642157557 is a wasteful number, since it uses less digits than its factorization.

642157557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6772.

The product of its digits is 294000, while the sum is 42.

The square root of 642157557 is about 25340.8278672975. The cubic root of 642157557 is about 862.7411889225.

The spelling of 642157557 in words is "six hundred forty-two million, one hundred fifty-seven thousand, five hundred fifty-seven".