81499408 has 10 divisors (see below), whose sum is σ = 157905134. Its totient is φ = 40749696.

The previous prime is 81499399. The next prime is 81499427. The reversal of 81499408 is 80499418.

It can be written as a sum of positive squares in only one way, i.e., 73479184 + 8020224 = 8572^2 + 2832^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2546841 + ... + 2546872.

Almost surely, 2^81499408 is an apocalyptic number.

It is an amenable number.

81499408 is a deficient number, since it is larger than the sum of its proper divisors (76405726).

81499408 is a wasteful number, since it uses less digits than its factorization.

81499408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5093721 (or 5093715 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 81499408 is about 9027.7022547268. The cubic root of 81499408 is about 433.5622732388.

The spelling of 81499408 in words is "eighty-one million, four hundred ninety-nine thousand, four hundred eight".