31121345 has 4 divisors (see below), whose sum is σ = 37345620. Its totient is φ = 24897072.

The previous prime is 31121341. The next prime is 31121357. The reversal of 31121345 is 54312113.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9480241 + 21641104 = 3079^2 + 4652^2 .

It is a cyclic number.

It is not a de Polignac number, because 31121345 - 2² = 31121341 is a prime.

It is a super-2 number, since 2×31121345² = 1937076229218050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31121341) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3112130 + ... + 3112139.

It is an arithmetic number, because the mean of its divisors is an integer number (9336405).

Almost surely, 2^31121345 is an apocalyptic number.

It is an amenable number.

31121345 is a deficient number, since it is larger than the sum of its proper divisors (6224275).

31121345 is an equidigital number, since it uses as much as digits as its factorization.

31121345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6224274.

The product of its digits is 360, while the sum is 20.

The square root of 31121345 is about 5578.6508225556. The cubic root of 31121345 is about 314.5474142090.

Adding to 31121345 its reverse (54312113), we get a palindrome (85433458).

The spelling of 31121345 in words is "thirty-one million, one hundred twenty-one thousand, three hundred forty-five".