20973761 has 4 divisors (see below), whose sum is σ = 21181524. Its totient is φ = 20766000.

The previous prime is 20973731. The next prime is 20973779. The reversal of 20973761 is 16737902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16737902 = 2 ⋅8368951.

It can be written as a sum of positive squares in 2 ways, for example, as 12673600 + 8300161 = 3560^2 + 2881^2 .

It is a cyclic number.

It is not a de Polignac number, because 20973761 - 2¹⁸ = 20711617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20973731) 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, 103730 + ... + 103931.

It is an arithmetic number, because the mean of its divisors is an integer number (5295381).

Almost surely, 2^20973761 is an apocalyptic number.

It is an amenable number.

20973761 is a deficient number, since it is larger than the sum of its proper divisors (207763).

20973761 is a wasteful number, since it uses less digits than its factorization.

20973761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207762.

The product of its (nonzero) digits is 15876, while the sum is 35.

The square root of 20973761 is about 4579.7118905014. The cubic root of 20973761 is about 275.7774627447. Note that the first 3 decimals are identical.

The spelling of 20973761 in words is "twenty million, nine hundred seventy-three thousand, seven hundred sixty-one".