81649374 has 16 divisors (see below), whose sum is σ = 163632000. Its totient is φ = 27160920.

The previous prime is 81649369. The next prime is 81649411. The reversal of 81649374 is 47394618.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10642 + ... + 16629.

It is an arithmetic number, because the mean of its divisors is an integer number (10227000).

Almost surely, 2^81649374 is an apocalyptic number.

81649374 is an abundant number, since it is smaller than the sum of its proper divisors (81982626).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81649374 is a wasteful number, since it uses less digits than its factorization.

81649374 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27775.

The product of its digits is 145152, while the sum is 42.

The square root of 81649374 is about 9036.0043160680. The cubic root of 81649374 is about 433.8280410590.

The spelling of 81649374 in words is "eighty-one million, six hundred forty-nine thousand, three hundred seventy-four".