81400737 has 16 divisors (see below), whose sum is σ = 118748160. Its totient is φ = 49189200.

The previous prime is 81400729. The next prime is 81400799. The reversal of 81400737 is 73700418.

It is a happy number.

It is not a de Polignac number, because 81400737 - 2³ = 81400729 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81400717) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8412 + ... + 15282.

It is an arithmetic number, because the mean of its divisors is an integer number (7421760).

Almost surely, 2^81400737 is an apocalyptic number.

It is an amenable number.

81400737 is a deficient number, since it is larger than the sum of its proper divisors (37347423).

81400737 is a wasteful number, since it uses less digits than its factorization.

81400737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7244.

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 81400737 is about 9022.2356985395. The cubic root of 81400737 is about 433.3872318888.

The spelling of 81400737 in words is "eighty-one million, four hundred thousand, seven hundred thirty-seven".