81502040 has 32 divisors (see below), whose sum is σ = 184222080. Its totient is φ = 32451072.

The previous prime is 81502033. The next prime is 81502049. The reversal of 81502040 is 4020518.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81502049) 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, 4352 + ... + 13488.

It is an arithmetic number, because the mean of its divisors is an integer number (5756940).

Almost surely, 2^81502040 is an apocalyptic number.

It is an amenable number.

81502040 is an abundant number, since it is smaller than the sum of its proper divisors (102720040).

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

81502040 is a wasteful number, since it uses less digits than its factorization.

81502040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9371 (or 9367 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 81502040 is about 9027.8480270771. The cubic root of 81502040 is about 433.5669404450.

Adding to 81502040 its reverse (4020518), we get a palindrome (85522558).

The spelling of 81502040 in words is "eighty-one million, five hundred two thousand, forty".