161868901 has 2 divisors, whose sum is σ = 161868902. Its totient is φ = 161868900.

The previous prime is 161868881. The next prime is 161868913. The reversal of 161868901 is 109868161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 143976001 + 17892900 = 11999^2 + 4230^2 .

It is a cyclic number.

It is not a de Polignac number, because 161868901 - 2⁵ = 161868869 is a prime.

It is a super-2 number, since 2×161868901² = 52403082221895602, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161868601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80934450 + 80934451.

It is an arithmetic number, because the mean of its divisors is an integer number (80934451).

Almost surely, 2^161868901 is an apocalyptic number.

It is an amenable number.

161868901 is a deficient number, since it is larger than the sum of its proper divisors (1).

161868901 is an equidigital number, since it uses as much as digits as its factorization.

161868901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 40.

The square root of 161868901 is about 12722.7709639056. The cubic root of 161868901 is about 544.9890871198.

The spelling of 161868901 in words is "one hundred sixty-one million, eight hundred sixty-eight thousand, nine hundred one".