20971537 has 2 divisors, whose sum is σ = 20971538. Its totient is φ = 20971536.

The previous prime is 20971529. The next prime is 20971567. The reversal of 20971537 is 73517902.

20971537 is nontrivially palindromic in base 8.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17842176 + 3129361 = 4224^2 + 1769^2 .

It is a cyclic number.

It is not a de Polignac number, because 20971537 - 2³ = 20971529 is a prime.

It is not a weakly prime, because it can be changed into another prime (20971507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10485768 + 10485769.

It is an arithmetic number, because the mean of its divisors is an integer number (10485769).

Almost surely, 2^20971537 is an apocalyptic number.

It is an amenable number.

20971537 is a deficient number, since it is larger than the sum of its proper divisors (1).

20971537 is an equidigital number, since it uses as much as digits as its factorization.

20971537 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13230, while the sum is 34.

The square root of 20971537 is about 4579.4690740303. The cubic root of 20971537 is about 275.7677148386.

It can be divided in two parts, 2097153 and 7, that multiplied together give a triangular number (14680071 = T₅₄₁₈).

The spelling of 20971537 in words is "twenty million, nine hundred seventy-one thousand, five hundred thirty-seven".