125381021 has 2 divisors, whose sum is σ = 125381022. Its totient is φ = 125381020.

The previous prime is 125380921. The next prime is 125381023. The reversal of 125381021 is 120183521.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 102292996 + 23088025 = 10114^2 + 4805^2 .

It is an emirp because it is prime and its reverse (120183521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 125381021 - 2¹⁰ = 125379997 is a prime.

Together with 125381023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125381023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62690510 + 62690511.

It is an arithmetic number, because the mean of its divisors is an integer number (62690511).

Almost surely, 2^125381021 is an apocalyptic number.

It is an amenable number.

125381021 is a deficient number, since it is larger than the sum of its proper divisors (1).

125381021 is an equidigital number, since it uses as much as digits as its factorization.

125381021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 125381021 is about 11197.3666993628. The cubic root of 125381021 is about 500.5075126875.

The spelling of 125381021 in words is "one hundred twenty-five million, three hundred eighty-one thousand, twenty-one".