167491021 has 4 divisors (see below), whose sum is σ = 177343452. Its totient is φ = 157638592.

The previous prime is 167491019. The next prime is 167491039. The reversal of 167491021 is 120194761.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120194761 = 43 ⋅2795227.

It can be written as a sum of positive squares in 2 ways, for example, as 112656996 + 54834025 = 10614^2 + 7405^2 .

It is a cyclic number.

It is not a de Polignac number, because 167491021 - 2¹ = 167491019 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 (167492021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4926190 + ... + 4926223.

It is an arithmetic number, because the mean of its divisors is an integer number (44335863).

Almost surely, 2^167491021 is an apocalyptic number.

It is an amenable number.

167491021 is a deficient number, since it is larger than the sum of its proper divisors (9852431).

167491021 is an equidigital number, since it uses as much as digits as its factorization.

167491021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9852430.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 167491021 is about 12941.8322118624. The cubic root of 167491021 is about 551.2270356862.

The spelling of 167491021 in words is "one hundred sixty-seven million, four hundred ninety-one thousand, twenty-one".