81298725 has 12 divisors (see below), whose sum is σ = 134414016. Its totient is φ = 43359280.

The previous prime is 81298717. The next prime is 81298747. The reversal of 81298725 is 52789218.

It is not a de Polignac number, because 81298725 - 2³ = 81298717 is a prime.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 541917 + ... + 542066.

It is an arithmetic number, because the mean of its divisors is an integer number (11201168).

Almost surely, 2^81298725 is an apocalyptic number.

It is an amenable number.

81298725 is a deficient number, since it is larger than the sum of its proper divisors (53115291).

81298725 is a wasteful number, since it uses less digits than its factorization.

81298725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1083996 (or 1083991 counting only the distinct ones).

The product of its digits is 80640, while the sum is 42.

The square root of 81298725 is about 9016.5805602789. The cubic root of 81298725 is about 433.2061148572.

The spelling of 81298725 in words is "eighty-one million, two hundred ninety-eight thousand, seven hundred twenty-five".