125212309 has 2 divisors, whose sum is σ = 125212310. Its totient is φ = 125212308.

The previous prime is 125212303. The next prime is 125212313. The reversal of 125212309 is 903212521.

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., 119968209 + 5244100 = 10953^2 + 2290^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-125212309 is a prime.

It is a super-2 number, since 2×125212309² = 31356244650222962, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125212303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62606154 + 62606155.

It is an arithmetic number, because the mean of its divisors is an integer number (62606155).

Almost surely, 2^125212309 is an apocalyptic number.

It is an amenable number.

125212309 is a deficient number, since it is larger than the sum of its proper divisors (1).

125212309 is an equidigital number, since it uses as much as digits as its factorization.

125212309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 125212309 is about 11189.8306064033. The cubic root of 125212309 is about 500.2829185507.

It can be divided in two parts, 125212 and 309, that added together give a palindrome (125521).

The spelling of 125212309 in words is "one hundred twenty-five million, two hundred twelve thousand, three hundred nine".