20157021 has 12 divisors (see below), whose sum is σ = 29240640. Its totient is φ = 13380360.

The previous prime is 20156963. The next prime is 20157029. The reversal of 20157021 is 12075102.

It is not a de Polignac number, because 20157021 - 2⁷ = 20156893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20156985 and 20157003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20157029) 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 11 ways as a sum of consecutive naturals, for example, 2535 + ... + 6836.

It is an arithmetic number, because the mean of its divisors is an integer number (2436720).

Almost surely, 2^20157021 is an apocalyptic number.

It is an amenable number.

20157021 is a deficient number, since it is larger than the sum of its proper divisors (9083619).

20157021 is a wasteful number, since it uses less digits than its factorization.

20157021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9616 (or 9613 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 20157021 is about 4489.6571138562. The cubic root of 20157021 is about 272.1502782963.

The spelling of 20157021 in words is "twenty million, one hundred fifty-seven thousand, twenty-one".