20956881 has 8 divisors (see below), whose sum is σ = 30482784. Its totient is φ = 12701120.

The previous prime is 20956861. The next prime is 20956907. The reversal of 20956881 is 18865902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20956881 - 2¹⁴ = 20940497 is a prime.

It is a super-2 number, since 2×20956881² = 878381722496322, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20956861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 317496 + ... + 317561.

It is an arithmetic number, because the mean of its divisors is an integer number (3810348).

Almost surely, 2^20956881 is an apocalyptic number.

It is an amenable number.

20956881 is a deficient number, since it is larger than the sum of its proper divisors (9525903).

20956881 is a wasteful number, since it uses less digits than its factorization.

20956881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635071.

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 20956881 is about 4577.8686088616. The cubic root of 20956881 is about 275.7034595975.

The spelling of 20956881 in words is "twenty million, nine hundred fifty-six thousand, eight hundred eighty-one".