73951981 has 2 divisors, whose sum is σ = 73951982. Its totient is φ = 73951980.

The previous prime is 73951961. The next prime is 73951991. The reversal of 73951981 is 18915937.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56025225 + 17926756 = 7485^2 + 4234^2 .

It is an emirp because it is prime and its reverse (18915937) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 73951981 - 2⁹ = 73951469 is a prime.

It is a super-2 number, since 2×73951981² = 10937790987648722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (73951901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36975990 + 36975991.

It is an arithmetic number, because the mean of its divisors is an integer number (36975991).

Almost surely, 2^73951981 is an apocalyptic number.

It is an amenable number.

73951981 is a deficient number, since it is larger than the sum of its proper divisors (1).

73951981 is an equidigital number, since it uses as much as digits as its factorization.

73951981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 43.

The square root of 73951981 is about 8599.5337664318. The cubic root of 73951981 is about 419.7428149573.

It can be divided in two parts, 739519 and 81, that added together give a square (739600 = 860²).

The spelling of 73951981 in words is "seventy-three million, nine hundred fifty-one thousand, nine hundred eighty-one".