661838715 has 32 divisors (see below), whose sum is σ = 1195905600. Its totient is φ = 347189760.

The previous prime is 661838707. The next prime is 661838729. The reversal of 661838715 is 517838166.

It is not a de Polignac number, because 661838715 - 2³ = 661838707 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 31950 + ... + 48419.

It is an arithmetic number, because the mean of its divisors is an integer number (37372050).

Almost surely, 2^661838715 is an apocalyptic number.

661838715 is a deficient number, since it is larger than the sum of its proper divisors (534066885).

661838715 is a wasteful number, since it uses less digits than its factorization.

661838715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80444 (or 80438 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 661838715 is about 25726.2262098427. The cubic root of 661838715 is about 871.4665514282.

The spelling of 661838715 in words is "six hundred sixty-one million, eight hundred thirty-eight thousand, seven hundred fifteen".