72743981 has 2 divisors, whose sum is σ = 72743982. Its totient is φ = 72743980.

The previous prime is 72743947. The next prime is 72743987. The reversal of 72743981 is 18934727.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68475625 + 4268356 = 8275^2 + 2066^2 .

It is a cyclic number.

It is not a de Polignac number, because 72743981 - 2¹⁴ = 72727597 is a prime.

It is a super-2 number, since 2×72743981² = 10583373543456722, which contains 22 as substring.

It is a Chen prime.

It is equal to p_4269893 and since 72743981 and 4269893 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72743987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36371990 + 36371991.

It is an arithmetic number, because the mean of its divisors is an integer number (36371991).

Almost surely, 2^72743981 is an apocalyptic number.

It is an amenable number.

72743981 is a deficient number, since it is larger than the sum of its proper divisors (1).

72743981 is an equidigital number, since it uses as much as digits as its factorization.

72743981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 41.

The square root of 72743981 is about 8529.0082072888. The cubic root of 72743981 is about 417.4447673357. Note that the first 3 decimals are identical.

The spelling of 72743981 in words is "seventy-two million, seven hundred forty-three thousand, nine hundred eighty-one".