20958161 has 16 divisors (see below), whose sum is σ = 25847424. Its totient is φ = 16583424.

The previous prime is 20958151. The next prime is 20958163. The reversal of 20958161 is 16185902.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20958161 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20958163) 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, 4646 + ... + 7968.

It is an arithmetic number, because the mean of its divisors is an integer number (1615464).

Almost surely, 2^20958161 is an apocalyptic number.

It is an amenable number.

20958161 is a deficient number, since it is larger than the sum of its proper divisors (4889263).

20958161 is a wasteful number, since it uses less digits than its factorization.

20958161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3400.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 20958161 is about 4578.0084097782. The cubic root of 20958161 is about 275.7090726026.

The spelling of 20958161 in words is "twenty million, nine hundred fifty-eight thousand, one hundred sixty-one".