125521515251 has 4 divisors (see below), whose sum is σ = 136932562104. Its totient is φ = 114110468400.

The previous prime is 125521515227. The next prime is 125521515257. The reversal of 125521515251 is 152515125521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 152515125521 = 11 ⋅13865011411.

It is a cyclic number.

It is not a de Polignac number, because 125521515251 - 2⁶ = 125521515187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (125521515257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5705523410 + ... + 5705523431.

It is an arithmetic number, because the mean of its divisors is an integer number (34233140526).

Almost surely, 2^125521515251 is an apocalyptic number.

125521515251 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

125521515251 is a deficient number, since it is larger than the sum of its proper divisors (11411046853).

125521515251 is a wasteful number, since it uses less digits than its factorization.

125521515251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11411046852.

The product of its digits is 25000, while the sum is 35.

The spelling of 125521515251 in words is "one hundred twenty-five billion, five hundred twenty-one million, five hundred fifteen thousand, two hundred fifty-one".