81512300 has 18 divisors (see below), whose sum is σ = 176881908. Its totient is φ = 32604880.

The previous prime is 81512293. The next prime is 81512303. The reversal of 81512300 is 321518.

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

It is not an unprimeable number, because it can be changed into a prime (81512303) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 407462 + ... + 407661.

Almost surely, 2^81512300 is an apocalyptic number.

It is an amenable number.

81512300 is an abundant number, since it is smaller than the sum of its proper divisors (95369608).

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

81512300 is a wasteful number, since it uses less digits than its factorization.

81512300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 815137 (or 815130 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 81512300 is about 9028.4162509268. The cubic root of 81512300 is about 433.5851330782.

Adding to 81512300 its reverse (321518), we get a palindrome (81833818).

The spelling of 81512300 in words is "eighty-one million, five hundred twelve thousand, three hundred".