166120551 has 20 divisors (see below), whose sum is σ = 250725552. Its totient is φ = 109600128.

The previous prime is 166120541. The next prime is 166120573. The reversal of 166120551 is 155021661.

It is a happy number.

It is not a de Polignac number, because 166120551 - 2⁵ = 166120519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166120541) 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, 2715 + ... + 18428.

Almost surely, 2^166120551 is an apocalyptic number.

166120551 is a deficient number, since it is larger than the sum of its proper divisors (84605001).

166120551 is an equidigital number, since it uses as much as digits as its factorization.

166120551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21252 (or 21243 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 166120551 is about 12888.7761637791. The cubic root of 166120551 is about 549.7194723681.

The spelling of 166120551 in words is "one hundred sixty-six million, one hundred twenty thousand, five hundred fifty-one".