645216374088 has 672 divisors, whose sum is σ = 2184180854520. Its totient is φ = 177367449600.

The previous prime is 645216374057. The next prime is 645216374129. The reversal of 645216374088 is 880473612546.

It is a happy number.

645216374088 is a `hidden beast` number, since 6 + 4 + 521 + 6 + 37 + 4 + 0 + 88 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 354956191524 + 290260182564 = 595782^2 + 538758^2 .

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 167 ways as a sum of consecutive naturals, for example, 559597320 + ... + 559598472.

Almost surely, 2^645216374088 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 645216374088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1092090427260).

645216374088 is an abundant number, since it is smaller than the sum of its proper divisors (1538964480432).

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

645216374088 is a wasteful number, since it uses less digits than its factorization.

645216374088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273 (or 1243 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 54.

The spelling of 645216374088 in words is "six hundred forty-five billion, two hundred sixteen million, three hundred seventy-four thousand, eighty-eight".