661521524 has 12 divisors (see below), whose sum is σ = 1195006848. Its totient is φ = 320091000.

The previous prime is 661521521. The next prime is 661521551. The reversal of 661521524 is 425125166.

It is a super-2 number, since 2×661521524² = 875221453430565152, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661521521) 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, 2667302 + ... + 2667549.

It is an arithmetic number, because the mean of its divisors is an integer number (99583904).

Almost surely, 2^661521524 is an apocalyptic number.

It is an amenable number.

661521524 is a deficient number, since it is larger than the sum of its proper divisors (533485324).

661521524 is a wasteful number, since it uses less digits than its factorization.

661521524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5334886 (or 5334884 counting only the distinct ones).

The product of its digits is 14400, while the sum is 32.

The square root of 661521524 is about 25720.0607308770. The cubic root of 661521524 is about 871.3273102952.

It can be divided in two parts, 66152 and 1524, that added together give a palindrome (67676).

The spelling of 661521524 in words is "six hundred sixty-one million, five hundred twenty-one thousand, five hundred twenty-four".