125521813 has 4 divisors (see below), whose sum is σ = 127034208. Its totient is φ = 124009420.

The previous prime is 125521811. The next prime is 125521817. The reversal of 125521813 is 318125521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 125521813 - 2¹ = 125521811 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (125521811) 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, 756073 + ... + 756238.

It is an arithmetic number, because the mean of its divisors is an integer number (31758552).

Almost surely, 2^125521813 is an apocalyptic number.

It is an amenable number.

125521813 is a deficient number, since it is larger than the sum of its proper divisors (1512395).

125521813 is an equidigital number, since it uses as much as digits as its factorization.

125521813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1512394.

The product of its digits is 2400, while the sum is 28.

The square root of 125521813 is about 11203.6517707398. The cubic root of 125521813 is about 500.6947847677.

It can be divided in two parts, 12552 and 1813, that added together give a triangular number (14365 = T₁₆₉).

The spelling of 125521813 in words is "one hundred twenty-five million, five hundred twenty-one thousand, eight hundred thirteen".