642012731 has 4 divisors (see below), whose sum is σ = 669926352. Its totient is φ = 614099112.

The previous prime is 642012671. The next prime is 642012737. The reversal of 642012731 is 137210246.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 137210246 = 2 ⋅68605123.

It is a cyclic number.

It is not a de Polignac number, because 642012731 - 2¹⁰ = 642011707 is a prime.

It is a super-2 number, since 2×642012731² = 824360693532156722, 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 642012731.

It is not an unprimeable number, because it can be changed into a prime (642012737) 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, 13956776 + ... + 13956821.

It is an arithmetic number, because the mean of its divisors is an integer number (167481588).

Almost surely, 2^642012731 is an apocalyptic number.

642012731 is a deficient number, since it is larger than the sum of its proper divisors (27913621).

642012731 is a wasteful number, since it uses less digits than its factorization.

642012731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27913620.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 642012731 is about 25337.9701436402. The cubic root of 642012731 is about 862.6763259470.

Adding to 642012731 its reverse (137210246), we get a palindrome (779222977).

The spelling of 642012731 in words is "six hundred forty-two million, twelve thousand, seven hundred thirty-one".