644515606476 has 180 divisors, whose sum is σ = 1965111337728. Its totient is φ = 183664780992.

The previous prime is 644515606421. The next prime is 644515606489. The reversal of 644515606476 is 674606515446.

644515606476 is a `hidden beast` number, since 6 + 4 + 4 + 5 + 1 + 560 + 6 + 4 + 76 = 666.

644515606476 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×644515606476² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 6027510 + ... + 6133506.

Almost surely, 2^644515606476 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644515606476, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (982555668864).

644515606476 is an abundant number, since it is smaller than the sum of its proper divisors (1320595731252).

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

644515606476 is a wasteful number, since it uses less digits than its factorization.

644515606476 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106410 (or 106392 counting only the distinct ones).

The product of its (nonzero) digits is 14515200, while the sum is 54.

The spelling of 644515606476 in words is "six hundred forty-four billion, five hundred fifteen million, six hundred six thousand, four hundred seventy-six".