20957407 has 2 divisors, whose sum is σ = 20957408. Its totient is φ = 20957406.

The previous prime is 20957371. The next prime is 20957473. The reversal of 20957407 is 70475902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20957407 - 2¹⁵ = 20924639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20957707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10478703 + 10478704.

It is an arithmetic number, because the mean of its divisors is an integer number (10478704).

Almost surely, 2^20957407 is an apocalyptic number.

20957407 is a deficient number, since it is larger than the sum of its proper divisors (1).

20957407 is an equidigital number, since it uses as much as digits as its factorization.

20957407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17640, while the sum is 34.

The square root of 20957407 is about 4577.9260588175. The cubic root of 20957407 is about 275.7057662195.

The spelling of 20957407 in words is "twenty million, nine hundred fifty-seven thousand, four hundred seven".