81251079 has 16 divisors (see below), whose sum is σ = 133335552. Its totient is φ = 42857568.

The previous prime is 81251077. The next prime is 81251113. The reversal of 81251079 is 97015218.

It is not a de Polignac number, because 81251079 - 2¹ = 81251077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81251077) 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, 148539 + ... + 149084.

It is an arithmetic number, because the mean of its divisors is an integer number (8333472).

Almost surely, 2^81251079 is an apocalyptic number.

81251079 is a deficient number, since it is larger than the sum of its proper divisors (52084473).

81251079 is a wasteful number, since it uses less digits than its factorization.

81251079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297646.

The product of its (nonzero) digits is 5040, while the sum is 33.

The square root of 81251079 is about 9013.9380406124. The cubic root of 81251079 is about 433.1214699379.

The spelling of 81251079 in words is "eighty-one million, two hundred fifty-one thousand, seventy-nine".