31242109 has 2 divisors, whose sum is σ = 31242110. Its totient is φ = 31242108.

The previous prime is 31242103. The next prime is 31242139. The reversal of 31242109 is 90124213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27594009 + 3648100 = 5253^2 + 1910^2 .

It is an emirp because it is prime and its reverse (90124213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31242109 - 2¹¹ = 31240061 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31242109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31242103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15621054 + 15621055.

It is an arithmetic number, because the mean of its divisors is an integer number (15621055).

Almost surely, 2^31242109 is an apocalyptic number.

It is an amenable number.

31242109 is a deficient number, since it is larger than the sum of its proper divisors (1).

31242109 is an equidigital number, since it uses as much as digits as its factorization.

31242109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 31242109 is about 5589.4641066922. The cubic root of 31242109 is about 314.9537481432.

The spelling of 31242109 in words is "thirty-one million, two hundred forty-two thousand, one hundred nine".