20171961 has 12 divisors (see below), whose sum is σ = 29410992. Its totient is φ = 13321656.

The previous prime is 20171953. The next prime is 20171981. The reversal of 20171961 is 16917102.

It is not a de Polignac number, because 20171961 - 2³ = 20171953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20171951) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9511 + ... + 11436.

It is an arithmetic number, because the mean of its divisors is an integer number (2450916).

Almost surely, 2^20171961 is an apocalyptic number.

It is an amenable number.

20171961 is a deficient number, since it is larger than the sum of its proper divisors (9239031).

20171961 is a wasteful number, since it uses less digits than its factorization.

20171961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21060 (or 21057 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 27.

The square root of 20171961 is about 4491.3206298371. The cubic root of 20171961 is about 272.2174992254.

The spelling of 20171961 in words is "twenty million, one hundred seventy-one thousand, nine hundred sixty-one".