81509294 has 16 divisors (see below), whose sum is σ = 123959808. Its totient is φ = 40192512.

The previous prime is 81509279. The next prime is 81509303. The reversal of 81509294 is 49290518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73754 + ... + 74850.

It is an arithmetic number, because the mean of its divisors is an integer number (7747488).

Almost surely, 2^81509294 is an apocalyptic number.

81509294 is a deficient number, since it is larger than the sum of its proper divisors (42450514).

81509294 is a wasteful number, since it uses less digits than its factorization.

81509294 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1579.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 81509294 is about 9028.2497750118. The cubic root of 81509294 is about 433.5798031140.

The spelling of 81509294 in words is "eighty-one million, five hundred nine thousand, two hundred ninety-four".