642763731 has 4 divisors (see below), whose sum is σ = 857018312. Its totient is φ = 428509152.

The previous prime is 642763729. The next prime is 642763739. The reversal of 642763731 is 137367246.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 642763731 - 2¹ = 642763729 is a prime.

It is a super-2 number, since 2×642763731² = 826290427778080722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 642763731.

It is not an unprimeable number, because it can be changed into a prime (642763739) 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, 107127286 + ... + 107127291.

It is an arithmetic number, because the mean of its divisors is an integer number (214254578).

Almost surely, 2^642763731 is an apocalyptic number.

642763731 is a deficient number, since it is larger than the sum of its proper divisors (214254581).

642763731 is a wasteful number, since it uses less digits than its factorization.

642763731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214254580.

The product of its digits is 127008, while the sum is 39.

The square root of 642763731 is about 25352.7854682676. The cubic root of 642763731 is about 863.0125692624.

The spelling of 642763731 in words is "six hundred forty-two million, seven hundred sixty-three thousand, seven hundred thirty-one".