642756811 has 8 divisors (see below), whose sum is σ = 661010544. Its totient is φ = 624730080.

The previous prime is 642756809. The next prime is 642756839. The reversal of 642756811 is 118657246.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 642756811 - 2¹ = 642756809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642756311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51000 + ... + 62341.

It is an arithmetic number, because the mean of its divisors is an integer number (82626318).

Almost surely, 2^642756811 is an apocalyptic number.

642756811 is a deficient number, since it is larger than the sum of its proper divisors (18253733).

642756811 is a wasteful number, since it uses less digits than its factorization.

642756811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113501.

The product of its digits is 80640, while the sum is 40.

The square root of 642756811 is about 25352.6489937442. The cubic root of 642756811 is about 863.0094721843.

The spelling of 642756811 in words is "six hundred forty-two million, seven hundred fifty-six thousand, eight hundred eleven".