20165551 has 16 divisors (see below), whose sum is σ = 23662080. Its totient is φ = 16829280.

The previous prime is 20165543. The next prime is 20165557. The reversal of 20165551 is 15556102.

It is a cyclic number.

It is not a de Polignac number, because 20165551 - 2³ = 20165543 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 (20165557) 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, 64686 + ... + 64996.

It is an arithmetic number, because the mean of its divisors is an integer number (1478880).

Almost surely, 2^20165551 is an apocalyptic number.

20165551 is a deficient number, since it is larger than the sum of its proper divisors (3496529).

20165551 is a wasteful number, since it uses less digits than its factorization.

20165551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534.

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

The square root of 20165551 is about 4490.6069745637. The cubic root of 20165551 is about 272.1886621840.

The spelling of 20165551 in words is "twenty million, one hundred sixty-five thousand, five hundred fifty-one".