661962871 has 6 divisors (see below), whose sum is σ = 683464416. Its totient is φ = 640470600.

The previous prime is 661962863. The next prime is 661962901. The reversal of 661962871 is 178269166.

It is not a de Polignac number, because 661962871 - 2³ = 661962863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661962811) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 140941 + ... + 145561.

It is an arithmetic number, because the mean of its divisors is an integer number (113910736).

Almost surely, 2^661962871 is an apocalyptic number.

661962871 is a deficient number, since it is larger than the sum of its proper divisors (21501545).

661962871 is an frugal number, since it uses more digits than its factorization.

661962871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9273 (or 4652 counting only the distinct ones).

The product of its digits is 217728, while the sum is 46.

The square root of 661962871 is about 25728.6391206375. The cubic root of 661962871 is about 871.5210415599.

The spelling of 661962871 in words is "six hundred sixty-one million, nine hundred sixty-two thousand, eight hundred seventy-one".