81472905 has 16 divisors (see below), whose sum is σ = 144840960. Its totient is φ = 43452144.

The previous prime is 81472901. The next prime is 81472907. The reversal of 81472905 is 50927418.

It is not a de Polignac number, because 81472905 - 2² = 81472901 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 81472905.

It is not an unprimeable number, because it can be changed into a prime (81472901) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 301617 + ... + 301886.

It is an arithmetic number, because the mean of its divisors is an integer number (9052560).

Almost surely, 2^81472905 is an apocalyptic number.

It is an amenable number.

81472905 is a deficient number, since it is larger than the sum of its proper divisors (63368055).

81472905 is a wasteful number, since it uses less digits than its factorization.

81472905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603517 (or 603511 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 81472905 is about 9026.2342646311. The cubic root of 81472905 is about 433.5152710704.

The spelling of 81472905 in words is "eighty-one million, four hundred seventy-two thousand, nine hundred five".