81470840 has 32 divisors (see below), whose sum is σ = 199974960. Its totient is φ = 29625600.

The previous prime is 81470833. The next prime is 81470843. The reversal of 81470840 is 4807418.

It is a junction number, because it is equal to n+sod(n) for n = 81470797 and 81470806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81470843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92141 + ... + 93020.

Almost surely, 2^81470840 is an apocalyptic number.

It is an amenable number.

81470840 is an abundant number, since it is smaller than the sum of its proper divisors (118504120).

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

81470840 is a wasteful number, since it uses less digits than its factorization.

81470840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185183 (or 185179 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 81470840 is about 9026.1198751180. The cubic root of 81470840 is about 433.5116084351.

The spelling of 81470840 in words is "eighty-one million, four hundred seventy thousand, eight hundred forty".