20963651 has 4 divisors (see below), whose sum is σ = 20976552. Its totient is φ = 20950752.

The previous prime is 20963639. The next prime is 20963653. The reversal of 20963651 is 15636902.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15636902 = 2 ⋅7818451.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20963651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20963653) 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, 3590 + ... + 7403.

It is an arithmetic number, because the mean of its divisors is an integer number (5244138).

Almost surely, 2^20963651 is an apocalyptic number.

20963651 is a deficient number, since it is larger than the sum of its proper divisors (12901).

20963651 is a wasteful number, since it uses less digits than its factorization.

20963651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12900.

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 20963651 is about 4578.6079762303. The cubic root of 20963651 is about 275.7331445407.

The spelling of 20963651 in words is "twenty million, nine hundred sixty-three thousand, six hundred fifty-one".