642961688 has 16 divisors (see below), whose sum is σ = 1257968880. Its totient is φ = 307503328.

The previous prime is 642961673. The next prime is 642961703. The reversal of 642961688 is 886169246.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (642961673) and next prime (642961703).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1746995 + ... + 1747362.

It is an arithmetic number, because the mean of its divisors is an integer number (78623055).

Almost surely, 2^642961688 is an apocalyptic number.

It is an amenable number.

642961688 is a deficient number, since it is larger than the sum of its proper divisors (615007192).

642961688 is a wasteful number, since it uses less digits than its factorization.

642961688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3494386 (or 3494382 counting only the distinct ones).

The product of its digits is 995328, while the sum is 50.

The square root of 642961688 is about 25356.6892160629. The cubic root of 642961688 is about 863.1011564242.

The spelling of 642961688 in words is "six hundred forty-two million, nine hundred sixty-one thousand, six hundred eighty-eight".