642391057 has 12 divisors (see below), whose sum is σ = 806971648. Its totient is φ = 500563800.

The previous prime is 642391027. The next prime is 642391063. The reversal of 642391057 is 750193246.

It is not a de Polignac number, because 642391057 - 2¹¹ = 642389009 is a prime.

It is a super-2 number, since 2×642391057² = 825332540227154498, which contains 22 as substring.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (642391027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 378369 + ... + 380062.

Almost surely, 2^642391057 is an apocalyptic number.

It is an amenable number.

642391057 is a deficient number, since it is larger than the sum of its proper divisors (164580591).

642391057 is a wasteful number, since it uses less digits than its factorization.

642391057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 758460 (or 758449 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 37.

The square root of 642391057 is about 25345.4346382144. The cubic root of 642391057 is about 862.8457456383.

The spelling of 642391057 in words is "six hundred forty-two million, three hundred ninety-one thousand, fifty-seven".