125549821 has 2 divisors, whose sum is σ = 125549822. Its totient is φ = 125549820.

The previous prime is 125549819. The next prime is 125549833. The reversal of 125549821 is 128945521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 122345721 + 3204100 = 11061^2 + 1790^2 .

It is a cyclic number.

It is not a de Polignac number, because 125549821 - 2¹ = 125549819 is a prime.

Together with 125549819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125549861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62774910 + 62774911.

It is an arithmetic number, because the mean of its divisors is an integer number (62774911).

Almost surely, 2^125549821 is an apocalyptic number.

It is an amenable number.

125549821 is a deficient number, since it is larger than the sum of its proper divisors (1).

125549821 is an equidigital number, since it uses as much as digits as its factorization.

125549821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28800, while the sum is 37.

The square root of 125549821 is about 11204.9016506170. The cubic root of 125549821 is about 500.7320224300.

It can be divided in two parts, 1255 and 49821, that added together give a square (51076 = 226²).

The spelling of 125549821 in words is "one hundred twenty-five million, five hundred forty-nine thousand, eight hundred twenty-one".