1251533520225 has 144 divisors (see below), whose sum is σ = 2401203604800. Its totient is φ = 621303644160.

The previous prime is 1251533520151. The next prime is 1251533520239. The reversal of 1251533520225 is 5220253351521.

1251533520225 is a `hidden beast` number, since 1 + 2 + 51 + 533 + 52 + 0 + 2 + 25 = 666.

It is not a de Polignac number, because 1251533520225 - 2⁸ = 1251533519969 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1251533520225.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 57628969 + ... + 57650681.

Almost surely, 2^{1251533520225} is an apocalyptic number.

1251533520225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1251533520225 is a deficient number, since it is larger than the sum of its proper divisors (1149670084575).

1251533520225 is a wasteful number, since it uses less digits than its factorization.

1251533520225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21984 (or 21976 counting only the distinct ones).

The product of its (nonzero) digits is 90000, while the sum is 36.

Adding to 1251533520225 its reverse (5220253351521), we get a palindrome (6471786871746).

The spelling of 1251533520225 in words is "one trillion, two hundred fifty-one billion, five hundred thirty-three million, five hundred twenty thousand, two hundred twenty-five".