20872291 has 4 divisors (see below), whose sum is σ = 22769784. Its totient is φ = 18974800.

The previous prime is 20872273. The next prime is 20872307. The reversal of 20872291 is 19227802.

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 20872291 - 2²¹ = 18775139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20872211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 948730 + ... + 948751.

It is an arithmetic number, because the mean of its divisors is an integer number (5692446).

Almost surely, 2^20872291 is an apocalyptic number.

20872291 is a deficient number, since it is larger than the sum of its proper divisors (1897493).

20872291 is a wasteful number, since it uses less digits than its factorization.

20872291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1897492.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 20872291 is about 4568.6202512356. The cubic root of 20872291 is about 275.3320111185.

The spelling of 20872291 in words is "twenty million, eight hundred seventy-two thousand, two hundred ninety-one".