20687157 has 20 divisors (see below), whose sum is σ = 31161856. Its totient is φ = 13676040.

The previous prime is 20687141. The next prime is 20687159. The reversal of 20687157 is 75178602.

It is not a de Polignac number, because 20687157 - 2⁴ = 20687141 is a prime.

It is a super-3 number, since 3×20687157³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20687159) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9282 + ... + 11292.

Almost surely, 2^20687157 is an apocalyptic number.

20687157 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

20687157 is a deficient number, since it is larger than the sum of its proper divisors (10474699).

20687157 is a wasteful number, since it uses less digits than its factorization.

20687157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2150 (or 2141 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 20687157 is about 4548.3136435387. The cubic root of 20687157 is about 274.5155415370.

The spelling of 20687157 in words is "twenty million, six hundred eighty-seven thousand, one hundred fifty-seven".