20156551 has 8 divisors (see below), whose sum is σ = 20793344. Its totient is φ = 19527480.

The previous prime is 20156519. The next prime is 20156557. The reversal of 20156551 is 15565102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20156551 - 2⁵ = 20156519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20156557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3616 + ... + 7306.

It is an arithmetic number, because the mean of its divisors is an integer number (2599168).

Almost surely, 2^20156551 is an apocalyptic number.

20156551 is a deficient number, since it is larger than the sum of its proper divisors (636793).

20156551 is a wasteful number, since it uses less digits than its factorization.

20156551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3861.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 20156551 is about 4489.6047710238. The cubic root of 20156551 is about 272.1481630428.

The spelling of 20156551 in words is "twenty million, one hundred fifty-six thousand, five hundred fifty-one".