661564440235342 has 64 divisors (see below), whose sum is σ = 1203178491624960. Its totient is φ = 266497227187200.

The previous prime is 661564440235301. The next prime is 661564440235367. The reversal of 661564440235342 is 243532044465166.

It is a Smith number, since the sum of its digits (55) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60984342 + ... + 71008582.

It is an arithmetic number, because the mean of its divisors is an integer number (18799663931640).

Almost surely, 2^{661564440235342} is an apocalyptic number.

661564440235342 is a deficient number, since it is larger than the sum of its proper divisors (541614051389618).

661564440235342 is a wasteful number, since it uses less digits than its factorization.

661564440235342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10026217.

The product of its (nonzero) digits is 49766400, while the sum is 55.

The spelling of 661564440235342 in words is "six hundred sixty-one trillion, five hundred sixty-four billion, four hundred forty million, two hundred thirty-five thousand, three hundred forty-two".