661778081496 has 96 divisors (see below), whose sum is σ = 2049320800800. Its totient is φ = 188990830080.

The previous prime is 661778081477. The next prime is 661778081537. The reversal of 661778081496 is 694180877166.

661778081496 is a `hidden beast` number, since 6 + 61 + 7 + 7 + 8 + 0 + 81 + 496 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 772420 + ... + 1385708.

It is an arithmetic number, because the mean of its divisors is an integer number (21347091675).

Almost surely, 2^661778081496 is an apocalyptic number.

It is an amenable number.

661778081496 is an abundant number, since it is smaller than the sum of its proper divisors (1387542719304).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661778081496 is a wasteful number, since it uses less digits than its factorization.

661778081496 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 615449 (or 615442 counting only the distinct ones).

The product of its (nonzero) digits is 24385536, while the sum is 63.

The spelling of 661778081496 in words is "six hundred sixty-one billion, seven hundred seventy-eight million, eighty-one thousand, four hundred ninety-six".