661521542 has 16 divisors (see below), whose sum is σ = 1082916864. Its totient is φ = 300573000.

The previous prime is 661521521. The next prime is 661521551. The reversal of 661521542 is 245125166.

It is a super-2 number, since 2×661521542² = 875221501060115528, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661521499 and 661521508.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76667 + ... + 84857.

It is an arithmetic number, because the mean of its divisors is an integer number (67682304).

Almost surely, 2^661521542 is an apocalyptic number.

661521542 is a deficient number, since it is larger than the sum of its proper divisors (421395322).

661521542 is a wasteful number, since it uses less digits than its factorization.

661521542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11875.

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

The square root of 661521542 is about 25720.0610807984. The cubic root of 661521542 is about 871.3273181981.

The spelling of 661521542 in words is "six hundred sixty-one million, five hundred twenty-one thousand, five hundred forty-two".