1990152181 has 2 divisors, whose sum is σ = 1990152182. Its totient is φ = 1990152180.

The previous prime is 1990152179. The next prime is 1990152233. The reversal of 1990152181 is 1812510991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1470722500 + 519429681 = 38350^2 + 22791^2 .

It is a cyclic number.

It is not a de Polignac number, because 1990152181 - 2¹ = 1990152179 is a prime.

It is a super-2 number, since 2×1990152181² = 7921411407078113522, which contains 22 as substring.

Together with 1990152179, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1990152181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1990252181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995076090 + 995076091.

It is an arithmetic number, because the mean of its divisors is an integer number (995076091).

Almost surely, 2^1990152181 is an apocalyptic number.

It is an amenable number.

1990152181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1990152181 is an equidigital number, since it uses as much as digits as its factorization.

1990152181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 37.

The square root of 1990152181 is about 44611.1217186925. The cubic root of 1990152181 is about 1257.8497340997.

The spelling of 1990152181 in words is "one billion, nine hundred ninety million, one hundred fifty-two thousand, one hundred eighty-one".