81144930 has 16 divisors (see below), whose sum is σ = 194747904. Its totient is φ = 21638640.

The previous prime is 81144919. The next prime is 81144971. The reversal of 81144930 is 3944118.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 2704831 = 81144930 / (8 + 1 + 1 + 4 + 4 + 9 + 3 + 0).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1352386 + ... + 1352445.

It is an arithmetic number, because the mean of its divisors is an integer number (12171744).

Almost surely, 2^81144930 is an apocalyptic number.

81144930 is an abundant number, since it is smaller than the sum of its proper divisors (113602974).

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

81144930 is a wasteful number, since it uses less digits than its factorization.

81144930 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2704841.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 81144930 is about 9008.0480682554. The cubic root of 81144930 is about 432.9327731752.

The spelling of 81144930 in words is "eighty-one million, one hundred forty-four thousand, nine hundred thirty".