31184478421 has 2 divisors, whose sum is σ = 31184478422. Its totient is φ = 31184478420.

The previous prime is 31184478397. The next prime is 31184478443. The reversal of 31184478421 is 12487448113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22365202500 + 8819275921 = 149550^2 + 93911^2 .

It is a cyclic number.

It is not a de Polignac number, because 31184478421 - 2⁷ = 31184478293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31184479421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15592239210 + 15592239211.

It is an arithmetic number, because the mean of its divisors is an integer number (15592239211).

Almost surely, 2^31184478421 is an apocalyptic number.

It is an amenable number.

31184478421 is a deficient number, since it is larger than the sum of its proper divisors (1).

31184478421 is an equidigital number, since it uses as much as digits as its factorization.

31184478421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 172032, while the sum is 43.

The spelling of 31184478421 in words is "thirty-one billion, one hundred eighty-four million, four hundred seventy-eight thousand, four hundred twenty-one".