1256508725481 has 45 divisors (see below), whose sum is σ = 1910264661613. Its totient is φ = 823084557480.

The previous prime is 1256508725429. The next prime is 1256508725501. The reversal of 1256508725481 is 1845278056521.

The square root of 1256508725481 is 1120941.

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

1256508725481 is a `hidden beast` number, since 1 + 2 + 5 + 6 + 508 + 7 + 2 + 54 + 81 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-1256508725481 is a prime.

It is a super-2 number, since 2×1256508725481² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256508725411) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 595218616 + ... + 595220726.

Almost surely, 2^{1256508725481} is an apocalyptic number.

1256508725481 is the 1120941-st square number.

1256508725481 is the 560471-st centered octagonal number.

It is an amenable number.

1256508725481 is a deficient number, since it is larger than the sum of its proper divisors (653755936132).

1256508725481 is an frugal number, since it uses more digits than its factorization.

1256508725481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4352 (or 2173 counting only the distinct ones).

The product of its (nonzero) digits is 5376000, while the sum is 54.

The spelling of 1256508725481 in words is "one trillion, two hundred fifty-six billion, five hundred eight million, seven hundred twenty-five thousand, four hundred eighty-one".