761911981 has 2 divisors, whose sum is σ = 761911982. Its totient is φ = 761911980.

The previous prime is 761911973. The next prime is 761911991. The reversal of 761911981 is 189119167.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 526289481 + 235622500 = 22941^2 + 15350^2 .

It is a cyclic number.

It is not a de Polignac number, because 761911981 - 2³ = 761911973 is a prime.

It is a super-2 number, since 2×761911981² = 1161019733582688722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (761911921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 380955990 + 380955991.

It is an arithmetic number, because the mean of its divisors is an integer number (380955991).

Almost surely, 2^761911981 is an apocalyptic number.

It is an amenable number.

761911981 is a deficient number, since it is larger than the sum of its proper divisors (1).

761911981 is an equidigital number, since it uses as much as digits as its factorization.

761911981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 43.

The square root of 761911981 is about 27602.7531416705. The cubic root of 761911981 is about 913.3451654419.

It can be divided in two parts, 7619 and 11981, that added together give a square (19600 = 140²).

The spelling of 761911981 in words is "seven hundred sixty-one million, nine hundred eleven thousand, nine hundred eighty-one".