661578535 has 16 divisors (see below), whose sum is σ = 798698880. Its totient is φ = 526072320.

The previous prime is 661578527. The next prime is 661578559. The reversal of 661578535 is 535875166.

It is not a de Polignac number, because 661578535 - 2³ = 661578527 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 932761 + ... + 933469.

It is an arithmetic number, because the mean of its divisors is an integer number (49918680).

Almost surely, 2^661578535 is an apocalyptic number.

661578535 is a deficient number, since it is larger than the sum of its proper divisors (137120345).

661578535 is a wasteful number, since it uses less digits than its factorization.

661578535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1578.

The product of its digits is 756000, while the sum is 46.

The square root of 661578535 is about 25721.1690053154. The cubic root of 661578535 is about 871.3523403774.

The spelling of 661578535 in words is "six hundred sixty-one million, five hundred seventy-eight thousand, five hundred thirty-five".