81737381 has 8 divisors (see below), whose sum is σ = 90052128. Its totient is φ = 73570000.

The previous prime is 81737363. The next prime is 81737389. The reversal of 81737381 is 18373718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81737381 - 2⁶ = 81737317 is a prime.

It is a super-2 number, since 2×81737381² = 13361998905478322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81737389) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35675 + ... + 37896.

It is an arithmetic number, because the mean of its divisors is an integer number (11256516).

Almost surely, 2^81737381 is an apocalyptic number.

It is an amenable number.

81737381 is a deficient number, since it is larger than the sum of its proper divisors (8314747).

81737381 is a wasteful number, since it uses less digits than its factorization.

81737381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73683.

The product of its digits is 28224, while the sum is 38.

The square root of 81737381 is about 9040.8728007864. The cubic root of 81737381 is about 433.9838544398.

The spelling of 81737381 in words is "eighty-one million, seven hundred thirty-seven thousand, three hundred eighty-one".