81497784 has 64 divisors (see below), whose sum is σ = 208484640. Its totient is φ = 26542080.

The previous prime is 81497761. The next prime is 81497789. The reversal of 81497784 is 48779418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81497789) 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, 316984 + ... + 317240.

Almost surely, 2^81497784 is an apocalyptic number.

It is an amenable number.

81497784 is an abundant number, since it is smaller than the sum of its proper divisors (126986856).

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

81497784 is a wasteful number, since it uses less digits than its factorization.

81497784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520 (or 516 counting only the distinct ones).

The product of its digits is 451584, while the sum is 48.

The square root of 81497784 is about 9027.6123089109. The cubic root of 81497784 is about 433.5593934232.

The spelling of 81497784 in words is "eighty-one million, four hundred ninety-seven thousand, seven hundred eighty-four".