125505551 has 4 divisors (see below), whose sum is σ = 128566704. Its totient is φ = 122444400.

The previous prime is 125505547. The next prime is 125505553. The reversal of 125505551 is 155505521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155505521 = 3691 ⋅42131.

It is a cyclic number.

It is not a de Polignac number, because 125505551 - 2² = 125505547 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 (125505553) 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, 1530515 + ... + 1530596.

It is an arithmetic number, because the mean of its divisors is an integer number (32141676).

Almost surely, 2^125505551 is an apocalyptic number.

125505551 is a deficient number, since it is larger than the sum of its proper divisors (3061153).

125505551 is an equidigital number, since it uses as much as digits as its factorization.

125505551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3061152.

The product of its (nonzero) digits is 6250, while the sum is 29.

The square root of 125505551 is about 11202.9260017194. The cubic root of 125505551 is about 500.6731613010.

The spelling of 125505551 in words is "one hundred twenty-five million, five hundred five thousand, five hundred fifty-one".