81628470 has 96 divisors (see below), whose sum is σ = 264625920. Its totient is φ = 16960320.

The previous prime is 81628457. The next prime is 81628513. The reversal of 81628470 is 7482618.

It is a super-2 number, since 2×81628470² = 13326414229081800, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

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, 1041 + ... + 12819.

It is an arithmetic number, because the mean of its divisors is an integer number (2756520).

Almost surely, 2^81628470 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81628470, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132312960).

81628470 is an abundant number, since it is smaller than the sum of its proper divisors (182997450).

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

81628470 is a wasteful number, since it uses less digits than its factorization.

81628470 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11810 (or 11807 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 81628470 is about 9034.8475360683. The cubic root of 81628470 is about 433.7910147885.

The spelling of 81628470 in words is "eighty-one million, six hundred twenty-eight thousand, four hundred seventy".