461681981 has 2 divisors, whose sum is σ = 461681982. Its totient is φ = 461681980.

The previous prime is 461681959. The next prime is 461681999. The reversal of 461681981 is 189186164.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 239940100 + 221741881 = 15490^2 + 14891^2 .

It is a cyclic number.

It is not a de Polignac number, because 461681981 - 2¹⁴ = 461665597 is a prime.

It is a super-2 number, since 2×461681981² = 426300503160168722, 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 (461681951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 230840990 + 230840991.

It is an arithmetic number, because the mean of its divisors is an integer number (230840991).

Almost surely, 2^461681981 is an apocalyptic number.

It is an amenable number.

461681981 is a deficient number, since it is larger than the sum of its proper divisors (1).

461681981 is an equidigital number, since it uses as much as digits as its factorization.

461681981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 44.

The square root of 461681981 is about 21486.7861952410. The cubic root of 461681981 is about 772.8839848716.

The spelling of 461681981 in words is "four hundred sixty-one million, six hundred eighty-one thousand, nine hundred eighty-one".