125515021 has 2 divisors, whose sum is σ = 125515022. Its totient is φ = 125515020.

The previous prime is 125514943. The next prime is 125515031. The reversal of 125515021 is 120515521.

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., 96236100 + 29278921 = 9810^2 + 5411^2 .

It is a cyclic number.

It is not a de Polignac number, because 125515021 - 2¹¹ = 125512973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 125514983 and 125515001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125515031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62757510 + 62757511.

It is an arithmetic number, because the mean of its divisors is an integer number (62757511).

Almost surely, 2^125515021 is an apocalyptic number.

It is an amenable number.

125515021 is a deficient number, since it is larger than the sum of its proper divisors (1).

125515021 is an equidigital number, since it uses as much as digits as its factorization.

125515021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 500, while the sum is 22.

The square root of 125515021 is about 11203.3486511846. The cubic root of 125515021 is about 500.6857537204.

Adding to 125515021 its product of nonzero digits (500), we get a palindrome (125515521).

The spelling of 125515021 in words is "one hundred twenty-five million, five hundred fifteen thousand, twenty-one".