81012140 has 48 divisors (see below), whose sum is σ = 196517664. Its totient is φ = 27724800.

The previous prime is 81012137. The next prime is 81012163. The reversal of 81012140 is 4121018.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7091 + ... + 14570.

It is an arithmetic number, because the mean of its divisors is an integer number (4094118).

Almost surely, 2^81012140 is an apocalyptic number.

It is an amenable number.

81012140 is an abundant number, since it is smaller than the sum of its proper divisors (115505524).

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

81012140 is a wasteful number, since it uses less digits than its factorization.

81012140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21698 (or 21696 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 81012140 is about 9000.6744191755. The cubic root of 81012140 is about 432.6964859504.

Adding to 81012140 its reverse (4121018), we get a palindrome (85133158).

The spelling of 81012140 in words is "eighty-one million, twelve thousand, one hundred forty".