20157861 has 16 divisors (see below), whose sum is σ = 27687744. Its totient is φ = 13039104.

The previous prime is 20157833. The next prime is 20157889. The reversal of 20157861 is 16875102.

It is an interprime number because it is at equal distance from previous prime (20157833) and next prime (20157889).

It is not a de Polignac number, because 20157861 - 2¹⁰ = 20156837 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20157811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14770 + ... + 16076.

It is an arithmetic number, because the mean of its divisors is an integer number (1730484).

Almost surely, 2^20157861 is an apocalyptic number.

It is an amenable number.

20157861 is a deficient number, since it is larger than the sum of its proper divisors (7529883).

20157861 is a wasteful number, since it uses less digits than its factorization.

20157861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1460.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 20157861 is about 4489.7506612283. The cubic root of 20157861 is about 272.1540586674.

The spelling of 20157861 in words is "twenty million, one hundred fifty-seven thousand, eight hundred sixty-one".