20164981 has 2 divisors, whose sum is σ = 20164982. Its totient is φ = 20164980.

The previous prime is 20164967. The next prime is 20165003. The reversal of 20164981 is 18946102.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18879025 + 1285956 = 4345^2 + 1134^2 .

It is a cyclic number.

It is not a de Polignac number, because 20164981 - 2⁷ = 20164853 is a prime.

It is a super-2 number, since 2×20164981² = 813252917460722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20164901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10082490 + 10082491.

It is an arithmetic number, because the mean of its divisors is an integer number (10082491).

Almost surely, 2^20164981 is an apocalyptic number.

It is an amenable number.

20164981 is a deficient number, since it is larger than the sum of its proper divisors (1).

20164981 is an equidigital number, since it uses as much as digits as its factorization.

20164981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 20164981 is about 4490.5435083072. The cubic root of 20164981 is about 272.1860975958.

The spelling of 20164981 in words is "twenty million, one hundred sixty-four thousand, nine hundred eighty-one".