81253650 has 48 divisors (see below), whose sum is σ = 208468800. Its totient is φ = 20919360.

The previous prime is 81253643. The next prime is 81253657. The reversal of 81253650 is 5635218.

It is an interprime number because it is at equal distance from previous prime (81253643) and next prime (81253657).

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

It is not an unprimeable number, because it can be changed into a prime (81253657) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4990 + ... + 13689.

It is an arithmetic number, because the mean of its divisors is an integer number (4343100).

Almost surely, 2^81253650 is an apocalyptic number.

81253650 is an abundant number, since it is smaller than the sum of its proper divisors (127215150).

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

81253650 is a wasteful number, since it uses less digits than its factorization.

81253650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18723 (or 18718 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 81253650 is about 9014.0806519578. The cubic root of 81253650 is about 433.1260382610.

Adding to 81253650 its reverse (5635218), we get a palindrome (86888868).

The spelling of 81253650 in words is "eighty-one million, two hundred fifty-three thousand, six hundred fifty".