661955893 has 16 divisors (see below), whose sum is σ = 698544000. Its totient is φ = 626063680.

The previous prime is 661955891. The next prime is 661955929. The reversal of 661955893 is 398559166.

It is not a de Polignac number, because 661955893 - 2¹ = 661955891 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661955893.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661955891) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1435683 + ... + 1436143.

It is an arithmetic number, because the mean of its divisors is an integer number (43659000).

Almost surely, 2^661955893 is an apocalyptic number.

It is an amenable number.

661955893 is a deficient number, since it is larger than the sum of its proper divisors (36588107).

661955893 is a wasteful number, since it uses less digits than its factorization.

661955893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1052.

The product of its digits is 1749600, while the sum is 52.

The square root of 661955893 is about 25728.5035126414. The cubic root of 661955893 is about 871.5179792052.

The spelling of 661955893 in words is "six hundred sixty-one million, nine hundred fifty-five thousand, eight hundred ninety-three".