81802520 has 32 divisors (see below), whose sum is σ = 184327920. Its totient is φ = 32672640.

The previous prime is 81802519. The next prime is 81802529. The reversal of 81802520 is 2520818.

It is a self number, because there is not a number n which added to its sum of digits gives 81802520.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81802529) 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, 39839 + ... + 41841.

Almost surely, 2^81802520 is an apocalyptic number.

It is an amenable number.

81802520 is an abundant number, since it is smaller than the sum of its proper divisors (102525400).

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

81802520 is a wasteful number, since it uses less digits than its factorization.

81802520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3035 (or 3031 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 26.

The square root of 81802520 is about 9044.4745563244. The cubic root of 81802520 is about 434.0991087976.

The spelling of 81802520 in words is "eighty-one million, eight hundred two thousand, five hundred twenty".