2505385631281 has 27 divisors (see below), whose sum is σ = 2728642034979. Its totient is φ = 2299348801152.

The previous prime is 2505385631269. The next prime is 2505385631303. The reversal of 2505385631281 is 1821365835052.

The square root of 2505385631281 is 1582841.

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

It can be written as a sum of positive squares in 13 ways, for example, as 1732885264881 + 772500366400 = 1316391^2 + 878920^2 .

It is not a de Polignac number, because 2505385631281 - 2²⁵ = 2505352076849 is a prime.

It is a super-2 number, since 2×2505385631281² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2505385631981) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 6440579835 + ... + 6440580223.

Almost surely, 2^{2505385631281} is an apocalyptic number.

2505385631281 is the 1582841-st square number.

2505385631281 is the 791421-st centered octagonal number.

It is an amenable number.

2505385631281 is a deficient number, since it is larger than the sum of its proper divisors (223256403698).

2505385631281 is an frugal number, since it uses more digits than its factorization.

2505385631281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1430 (or 715 counting only the distinct ones).

The product of its (nonzero) digits is 1728000, while the sum is 49.

Multiplying 2505385631281 by its sum of digits (49), we get a square (122763895932769 = 11079887²).

The spelling of 2505385631281 in words is "two trillion, five hundred five billion, three hundred eighty-five million, six hundred thirty-one thousand, two hundred eighty-one".