124991521 has 2 divisors, whose sum is σ = 124991522.
Its totient is φ = 124991520.
The previous prime is 124991507. The next prime is 124991527. The reversal of 124991521 is 125199421.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 117483921 + 7507600 = 10839^2 + 2740^2
It is a cyclic number.
It is not a de Polignac number, because 124991521 - 27 = 124991393 is a prime.
It is not a weakly prime, because it can be changed into another prime (124991527) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62495760 + 62495761.
It is an arithmetic number, because the mean of its divisors is an integer number (62495761).
Almost surely, 2124991521 is an apocalyptic number.
It is an amenable number.
124991521 is a deficient number, since it is larger than the sum of its proper divisors (1).
124991521 is an equidigital number, since it uses as much as digits as its factorization.
124991521 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 6480, while the sum is 34.
The square root of 124991521 is about 11179.9606886608.
The cubic root of 124991521 is about 499.9886944110.
The spelling of 124991521 in words is "one hundred twenty-four million, nine hundred ninety-one thousand, five hundred twenty-one".