31440221357 has 2 divisors, whose sum is σ = 31440221358. Its totient is φ = 31440221356.

The previous prime is 31440221317. The next prime is 31440221411. The reversal of 31440221357 is 75312204413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28623902596 + 2816318761 = 169186^2 + 53069^2 .

It is a cyclic number.

It is not a de Polignac number, because 31440221357 - 2¹² = 31440217261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31440221317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15720110678 + 15720110679.

It is an arithmetic number, because the mean of its divisors is an integer number (15720110679).

Almost surely, 2^31440221357 is an apocalyptic number.

It is an amenable number.

31440221357 is a deficient number, since it is larger than the sum of its proper divisors (1).

31440221357 is an equidigital number, since it uses as much as digits as its factorization.

31440221357 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 32.

The spelling of 31440221357 in words is "thirty-one billion, four hundred forty million, two hundred twenty-one thousand, three hundred fifty-seven".