166427054236921 has 3 divisors (see below), whose sum is σ = 166427067137583. Its totient is φ = 166427041336260.

The previous prime is 166427054236871. The next prime is 166427054236943. The reversal of 166427054236921 is 129632450724661.

The square root of 166427054236921 is 12900661.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 38384703500521 + 128042350736400 = 6195539^2 + 11315580^2 .

It is not a de Polignac number, because 166427054236921 - 2¹⁷ = 166427054105849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166427054236951) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 6450331 + ... + 19350991.

It is an arithmetic number, because the mean of its divisors is an integer number (55475689045861).

Almost surely, 2^{166427054236921} is an apocalyptic number.

166427054236921 is the 12900661-st square number.

166427054236921 is the 6450331-st centered octagonal number.

It is an amenable number.

166427054236921 is a deficient number, since it is larger than the sum of its proper divisors (12900662).

166427054236921 is an frugal number, since it uses more digits than its factorization.

166427054236921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25801322 (or 12900661 counting only the distinct ones).

The product of its (nonzero) digits is 26127360, while the sum is 58.

The spelling of 166427054236921 in words is "one hundred sixty-six trillion, four hundred twenty-seven billion, fifty-four million, two hundred thirty-six thousand, nine hundred twenty-one".