31430381 has 2 divisors, whose sum is σ = 31430382. Its totient is φ = 31430380.

The previous prime is 31430363. The next prime is 31430393. The reversal of 31430381 is 18303413.

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., 22005481 + 9424900 = 4691^2 + 3070^2 .

It is an emirp because it is prime and its reverse (18303413) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31430381 - 2¹⁴ = 31413997 is a prime.

It is a super-2 number, since 2×31430381² = 1975737699610322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31430081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15715190 + 15715191.

It is an arithmetic number, because the mean of its divisors is an integer number (15715191).

Almost surely, 2^31430381 is an apocalyptic number.

It is an amenable number.

31430381 is a deficient number, since it is larger than the sum of its proper divisors (1).

31430381 is an equidigital number, since it uses as much as digits as its factorization.

31430381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 31430381 is about 5606.2804960152. The cubic root of 31430381 is about 315.5851423185.

Adding to 31430381 its reverse (18303413), we get a palindrome (49733794).

The spelling of 31430381 in words is "thirty-one million, four hundred thirty thousand, three hundred eighty-one".