642997907 has 4 divisors (see below), whose sum is σ = 643062096. Its totient is φ = 642933720.

The previous prime is 642997891. The next prime is 642997909. The reversal of 642997907 is 709799246.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 642997907 - 2⁴ = 642997891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642997909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13463 + ... + 38304.

It is an arithmetic number, because the mean of its divisors is an integer number (160765524).

Almost surely, 2^642997907 is an apocalyptic number.

642997907 is a deficient number, since it is larger than the sum of its proper divisors (64189).

642997907 is a wasteful number, since it uses less digits than its factorization.

642997907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64188.

The product of its (nonzero) digits is 1714608, while the sum is 53.

The square root of 642997907 is about 25357.4033962470. The cubic root of 642997907 is about 863.1173627158.

The spelling of 642997907 in words is "six hundred forty-two million, nine hundred ninety-seven thousand, nine hundred seven".