643656524442 has 16 divisors (see below), whose sum is σ = 1296574295520. Its totient is φ = 213008633712.

The previous prime is 643656524431. The next prime is 643656524453. The reversal of 643656524442 is 244425656346.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (643656524431) and next prime (643656524453).

It is a super-2 number, since 2×643656524442² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 385884373 + ... + 385886040.

It is an arithmetic number, because the mean of its divisors is an integer number (81035893470).

Almost surely, 2^643656524442 is an apocalyptic number.

643656524442 is an abundant number, since it is smaller than the sum of its proper divisors (652917771078).

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

643656524442 is a wasteful number, since it uses less digits than its factorization.

643656524442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771770557.

The product of its digits is 16588800, while the sum is 51.

The spelling of 643656524442 in words is "six hundred forty-three billion, six hundred fifty-six million, five hundred twenty-four thousand, four hundred forty-two".