20157999 has 16 divisors (see below), whose sum is σ = 27795840. Its totient is φ = 12987360.

The previous prime is 20157983. The next prime is 20158003. The reversal of 20157999 is 99975102.

It is not a de Polignac number, because 20157999 - 2⁴ = 20157983 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20157999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20167999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9864 + ... + 11730.

It is an arithmetic number, because the mean of its divisors is an integer number (1737240).

Almost surely, 2^20157999 is an apocalyptic number.

20157999 is a deficient number, since it is larger than the sum of its proper divisors (7637841).

20157999 is a wasteful number, since it uses less digits than its factorization.

20157999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1990.

The product of its (nonzero) digits is 51030, while the sum is 42.

The square root of 20157999 is about 4489.7660295387. The cubic root of 20157999 is about 272.1546797183.

The spelling of 20157999 in words is "twenty million, one hundred fifty-seven thousand, nine hundred ninety-nine".