661371500 has 24 divisors (see below), whose sum is σ = 1444436448. Its totient is φ = 264548400.

The previous prime is 661371497. The next prime is 661371521. The reversal of 661371500 is 5173166.

It is a super-2 number, since 2×661371500² = 874824522024500000, which contains 22 as substring.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

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, 660872 + ... + 661871.

It is an arithmetic number, because the mean of its divisors is an integer number (60184852).

Almost surely, 2^661371500 is an apocalyptic number.

It is an amenable number.

661371500 is an abundant number, since it is smaller than the sum of its proper divisors (783064948).

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

661371500 is a wasteful number, since it uses less digits than its factorization.

661371500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1322762 (or 1322750 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 661371500 is about 25717.1440871649. The cubic root of 661371500 is about 871.2614369579.

The spelling of 661371500 in words is "six hundred sixty-one million, three hundred seventy-one thousand, five hundred".