661138495 has 4 divisors (see below), whose sum is σ = 793366200. Its totient is φ = 528910792.

The previous prime is 661138487. The next prime is 661138523. The reversal of 661138495 is 594831166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661138495 - 2³ = 661138487 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66113845 + ... + 66113854.

It is an arithmetic number, because the mean of its divisors is an integer number (198341550).

Almost surely, 2^661138495 is an apocalyptic number.

661138495 is a deficient number, since it is larger than the sum of its proper divisors (132227705).

661138495 is a wasteful number, since it uses less digits than its factorization.

661138495 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132227704.

The product of its digits is 155520, while the sum is 43.

The square root of 661138495 is about 25712.6135388840. The cubic root of 661138495 is about 871.1591081275.

The spelling of 661138495 in words is "six hundred sixty-one million, one hundred thirty-eight thousand, four hundred ninety-five".