20157391 has 2 divisors, whose sum is σ = 20157392. Its totient is φ = 20157390.

The previous prime is 20157383. The next prime is 20157413. The reversal of 20157391 is 19375102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20157391 - 2³ = 20157383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20157301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10078695 + 10078696.

It is an arithmetic number, because the mean of its divisors is an integer number (10078696).

Almost surely, 2^20157391 is an apocalyptic number.

20157391 is a deficient number, since it is larger than the sum of its proper divisors (1).

20157391 is an equidigital number, since it uses as much as digits as its factorization.

20157391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 20157391 is about 4489.6983194865. The cubic root of 20157391 is about 272.1519434727.

The spelling of 20157391 in words is "twenty million, one hundred fifty-seven thousand, three hundred ninety-one".