81251455 has 4 divisors (see below), whose sum is σ = 97501752. Its totient is φ = 65001160.

The previous prime is 81251453. The next prime is 81251473. The reversal of 81251455 is 55415218.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81251455 - 2¹ = 81251453 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81251453) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8125141 + ... + 8125150.

It is an arithmetic number, because the mean of its divisors is an integer number (24375438).

Almost surely, 2^81251455 is an apocalyptic number.

81251455 is a deficient number, since it is larger than the sum of its proper divisors (16250297).

81251455 is a wasteful number, since it uses less digits than its factorization.

81251455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16250296.

The product of its digits is 8000, while the sum is 31.

The square root of 81251455 is about 9013.9588971772. The cubic root of 81251455 is about 433.1221380456.

The spelling of 81251455 in words is "eighty-one million, two hundred fifty-one thousand, four hundred fifty-five".