661012534 has 16 divisors (see below), whose sum is σ = 1220331168. Its totient is φ = 261499392.

The previous prime is 661012519. The next prime is 661012567. The reversal of 661012534 is 435210166.

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, 1815787 + ... + 1816150.

It is an arithmetic number, because the mean of its divisors is an integer number (76270698).

Almost surely, 2^661012534 is an apocalyptic number.

661012534 is a deficient number, since it is larger than the sum of its proper divisors (559318634).

661012534 is a wasteful number, since it uses less digits than its factorization.

661012534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3631959.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 661012534 is about 25710.1640212582. The cubic root of 661012534 is about 871.1037798099.

It can be divided in two parts, 66101 and 2534, that added together give a triangular number (68635 = T₃₇₀).

The spelling of 661012534 in words is "six hundred sixty-one million, twelve thousand, five hundred thirty-four".