20960921 has 4 divisors (see below), whose sum is σ = 20976144. Its totient is φ = 20945700.

The previous prime is 20960911. The next prime is 20960923. The reversal of 20960921 is 12906902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12906902 = 2 ⋅6453451.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20960921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20960923) 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, 5315 + ... + 8376.

It is an arithmetic number, because the mean of its divisors is an integer number (5244036).

Almost surely, 2^20960921 is an apocalyptic number.

It is an amenable number.

20960921 is a deficient number, since it is larger than the sum of its proper divisors (15223).

20960921 is a wasteful number, since it uses less digits than its factorization.

20960921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15222.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 20960921 is about 4578.3098409784. The cubic root of 20960921 is about 275.7211748674.

The spelling of 20960921 in words is "twenty million, nine hundred sixty thousand, nine hundred twenty-one".