31401870221 has 2 divisors, whose sum is σ = 31401870222. Its totient is φ = 31401870220.

The previous prime is 31401870211. The next prime is 31401870233. The reversal of 31401870221 is 12207810413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31147308196 + 254562025 = 176486^2 + 15955^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31401870221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31401870211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15700935110 + 15700935111.

It is an arithmetic number, because the mean of its divisors is an integer number (15700935111).

Almost surely, 2^31401870221 is an apocalyptic number.

It is an amenable number.

31401870221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31401870221 is an equidigital number, since it uses as much as digits as its factorization.

31401870221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 29.

The spelling of 31401870221 in words is "thirty-one billion, four hundred one million, eight hundred seventy thousand, two hundred twenty-one".