3957761981 has 2 divisors, whose sum is σ = 3957761982. Its totient is φ = 3957761980.

The previous prime is 3957761963. The next prime is 3957762023. The reversal of 3957761981 is 1891677593.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3053557081 + 904204900 = 55259^2 + 30070^2 .

It is a cyclic number.

It is not a de Polignac number, because 3957761981 - 2¹⁰ = 3957760957 is a prime.

It is a super-2 number, since 2×3957761981² = 31327759796498088722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3957761881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1978880990 + 1978880991.

It is an arithmetic number, because the mean of its divisors is an integer number (1978880991).

Almost surely, 2^3957761981 is an apocalyptic number.

It is an amenable number.

3957761981 is a deficient number, since it is larger than the sum of its proper divisors (1).

3957761981 is an equidigital number, since it uses as much as digits as its factorization.

3957761981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2857680, while the sum is 56.

The square root of 3957761981 is about 62910.7461488099. The cubic root of 3957761981 is about 1581.7938794385.

The spelling of 3957761981 in words is "three billion, nine hundred fifty-seven million, seven hundred sixty-one thousand, nine hundred eighty-one".