661173572 has 12 divisors (see below), whose sum is σ = 1188325740. Its totient is φ = 321651936.

The previous prime is 661173563. The next prime is 661173577. The reversal of 661173572 is 275371166.

It can be written as a sum of positive squares in 2 ways, for example, as 337677376 + 323496196 = 18376^2 + 17986^2 .

It is a super-2 number, since 2×661173572² = 874300984622478368, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661173577) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2233547 + ... + 2233842.

It is an arithmetic number, because the mean of its divisors is an integer number (99027145).

Almost surely, 2^661173572 is an apocalyptic number.

It is an amenable number.

661173572 is a deficient number, since it is larger than the sum of its proper divisors (527152168).

661173572 is a wasteful number, since it uses less digits than its factorization.

661173572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4467430 (or 4467428 counting only the distinct ones).

The product of its digits is 52920, while the sum is 38.

The square root of 661173572 is about 25713.2956269709. The cubic root of 661173572 is about 871.1745144344.

The spelling of 661173572 in words is "six hundred sixty-one million, one hundred seventy-three thousand, five hundred seventy-two".