31402309 has 2 divisors, whose sum is σ = 31402310. Its totient is φ = 31402308.

The previous prime is 31402289. The next prime is 31402313. The reversal of 31402309 is 90320413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20657025 + 10745284 = 4545^2 + 3278^2 .

It is a cyclic number.

It is not a de Polignac number, because 31402309 - 2¹¹ = 31400261 is a prime.

It is a super-2 number, since 2×31402309² = 1972210021062962, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31402309.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31402339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15701154 + 15701155.

It is an arithmetic number, because the mean of its divisors is an integer number (15701155).

Almost surely, 2^31402309 is an apocalyptic number.

It is an amenable number.

31402309 is a deficient number, since it is larger than the sum of its proper divisors (1).

31402309 is an equidigital number, since it uses as much as digits as its factorization.

31402309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 31402309 is about 5603.7763160212. The cubic root of 31402309 is about 315.4911595260.

The spelling of 31402309 in words is "thirty-one million, four hundred two thousand, three hundred nine".