164020621 has 4 divisors (see below), whose sum is σ = 165553632. Its totient is φ = 162487612.

The previous prime is 164020609. The next prime is 164020631. The reversal of 164020621 is 126020461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 126020461 = 7 ⋅18002923.

It is a cyclic number.

It is not a de Polignac number, because 164020621 - 2¹⁷ = 163889549 is a prime.

It is a super-2 number, since 2×164020621² = 53805528226451282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 164020592 and 164020601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164020601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 766345 + ... + 766558.

It is an arithmetic number, because the mean of its divisors is an integer number (41388408).

Almost surely, 2^164020621 is an apocalyptic number.

It is an amenable number.

164020621 is a deficient number, since it is larger than the sum of its proper divisors (1533011).

164020621 is a wasteful number, since it uses less digits than its factorization.

164020621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1533010.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 164020621 is about 12807.0535643449. The cubic root of 164020621 is about 547.3933082345.

The spelling of 164020621 in words is "one hundred sixty-four million, twenty thousand, six hundred twenty-one".