73531781 has 2 divisors, whose sum is σ = 73531782. Its totient is φ = 73531780.

The previous prime is 73531739. The next prime is 73531807. The reversal of 73531781 is 18713537.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73530625 + 1156 = 8575^2 + 34^2 .

It is a cyclic number.

It is not a de Polignac number, because 73531781 - 2¹⁴ = 73515397 is a prime.

It is a super-2 number, since 2×73531781² = 10813845634063922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (73531181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36765890 + 36765891.

It is an arithmetic number, because the mean of its divisors is an integer number (36765891).

Almost surely, 2^73531781 is an apocalyptic number.

It is an amenable number.

73531781 is a deficient number, since it is larger than the sum of its proper divisors (1).

73531781 is an equidigital number, since it uses as much as digits as its factorization.

73531781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17640, while the sum is 35.

The square root of 73531781 is about 8575.0674049829. The cubic root of 73531781 is about 418.9463023786.

The spelling of 73531781 in words is "seventy-three million, five hundred thirty-one thousand, seven hundred eighty-one".