31111621 has 2 divisors, whose sum is σ = 31111622. Its totient is φ = 31111620.

The previous prime is 31111609. The next prime is 31111627. The reversal of 31111621 is 12611113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28238596 + 2873025 = 5314^2 + 1695^2 .

It is a cyclic number.

It is not a de Polignac number, because 31111621 - 2¹⁷ = 30980549 is a prime.

It is a super-2 number, since 2×31111621² = 1935865922495282, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31111595 and 31111604.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31111627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15555810 + 15555811.

It is an arithmetic number, because the mean of its divisors is an integer number (15555811).

Almost surely, 2^31111621 is an apocalyptic number.

It is an amenable number.

31111621 is a deficient number, since it is larger than the sum of its proper divisors (1).

31111621 is an equidigital number, since it uses as much as digits as its factorization.

31111621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36, while the sum is 16.

The square root of 31111621 is about 5577.7792175740. The cubic root of 31111621 is about 314.5146502258.

Adding to 31111621 its reverse (12611113), we get a palindrome (43722734).

The spelling of 31111621 in words is "thirty-one million, one hundred eleven thousand, six hundred twenty-one".