645686152 has 8 divisors (see below), whose sum is σ = 1210661550. Its totient is φ = 322843072.

The previous prime is 645686143. The next prime is 645686179. The reversal of 645686152 is 251686546.

It can be written as a sum of positive squares in only one way, i.e., 428241636 + 217444516 = 20694^2 + 14746^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 645686099 and 645686108.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40355377 + ... + 40355392.

Almost surely, 2^645686152 is an apocalyptic number.

It is an amenable number.

645686152 is a deficient number, since it is larger than the sum of its proper divisors (564975398).

645686152 is a wasteful number, since it uses less digits than its factorization.

645686152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80710775 (or 80710771 counting only the distinct ones).

The product of its digits is 345600, while the sum is 43.

The square root of 645686152 is about 25410.3552119997. The cubic root of 645686152 is about 864.3185303869.

The spelling of 645686152 in words is "six hundred forty-five million, six hundred eighty-six thousand, one hundred fifty-two".