250991428458681 has 81 divisors (see below), whose sum is σ = 378272439544909. Its totient is φ = 166529431607616.

The previous prime is 250991428458679. The next prime is 250991428458769. The reversal of 250991428458681 is 186854824199052.

The square root of 250991428458681 is 15842709.

It is a perfect power (a square), and thus also a powerful number.

250991428458681 is a `hidden beast` number, since 2 + 5 + 0 + 9 + 9 + 1 + 428 + 45 + 86 + 81 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 211135691799081 + 39855736659600 = 14530509^2 + 6313140^2 .

It is a tau number, because it is divible by the number of its divisors (81).

It is not a de Polignac number, because 250991428458681 - 2¹ = 250991428458679 is a prime.

It is a super-2 number, since 2×250991428458681² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (250991428458601) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 406793238685 + ... + 406793239301.

Almost surely, 2^{250991428458681} is an apocalyptic number.

250991428458681 is the 15842709-th square number.

250991428458681 is the 7921355-th centered octagonal number.

It is an amenable number.

250991428458681 is a deficient number, since it is larger than the sum of its proper divisors (127281011086228).

250991428458681 is an frugal number, since it uses more digits than its factorization.

250991428458681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1892 (or 937 counting only the distinct ones).

The product of its (nonzero) digits is 398131200, while the sum is 72.

The spelling of 250991428458681 in words is "two hundred fifty trillion, nine hundred ninety-one billion, four hundred twenty-eight million, four hundred fifty-eight thousand, six hundred eighty-one".