81409758251 has 8 divisors (see below), whose sum is σ = 82508099520. Its totient is φ = 80313113088.

The previous prime is 81409758239. The next prime is 81409758277. The reversal of 81409758251 is 15285790418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81409758251 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81409758251.

It is not an unprimeable number, because it can be changed into a prime (81409758211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 327236 + ... + 519521.

It is an arithmetic number, because the mean of its divisors is an integer number (10313512440).

Almost surely, 2^81409758251 is an apocalyptic number.

81409758251 is a deficient number, since it is larger than the sum of its proper divisors (1098341269).

81409758251 is a wasteful number, since it uses less digits than its factorization.

81409758251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 848053.

The product of its (nonzero) digits is 806400, while the sum is 50.

The spelling of 81409758251 in words is "eighty-one billion, four hundred nine million, seven hundred fifty-eight thousand, two hundred fifty-one".