81471810 has 96 divisors (see below), whose sum is σ = 239509440. Its totient is φ = 17635968.

The previous prime is 81471763. The next prime is 81471857. The reversal of 81471810 is 1817418.

It is an interprime number because it is at equal distance from previous prime (81471763) and next prime (81471857).

It is a super-2 number, since 2×81471810² = 13275311649352200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 26472 + ... + 29388.

It is an arithmetic number, because the mean of its divisors is an integer number (2494890).

Almost surely, 2^81471810 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81471810, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119754720).

81471810 is an abundant number, since it is smaller than the sum of its proper divisors (158037630).

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

81471810 is a wasteful number, since it uses less digits than its factorization.

81471810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2960 (or 2953 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 30.

The square root of 81471810 is about 9026.1736079027. The cubic root of 81471810 is about 433.5133289059.

The spelling of 81471810 in words is "eighty-one million, four hundred seventy-one thousand, eight hundred ten".