642531720 has 64 divisors (see below), whose sum is σ = 1963984320. Its totient is φ = 168107264.

The previous prime is 642531691. The next prime is 642531733. The reversal of 642531720 is 27135246.

It is a super-3 number, since 3×642531720³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44154 + ... + 56873.

It is an arithmetic number, because the mean of its divisors is an integer number (30687255).

Almost surely, 2^642531720 is an apocalyptic number.

642531720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

642531720 is an abundant number, since it is smaller than the sum of its proper divisors (1321452600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642531720 is a wasteful number, since it uses less digits than its factorization.

642531720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101094 (or 101090 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 30.

The square root of 642531720 is about 25348.2094042163. The cubic root of 642531720 is about 862.9087195398.

Adding to 642531720 its reverse (27135246), we get a palindrome (669666966).

The spelling of 642531720 in words is "six hundred forty-two million, five hundred thirty-one thousand, seven hundred twenty".