31755421 has 2 divisors, whose sum is σ = 31755422. Its totient is φ = 31755420.

The previous prime is 31755419. The next prime is 31755463. The reversal of 31755421 is 12455713.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22934521 + 8820900 = 4789^2 + 2970^2 .

It is a cyclic number.

It is not a de Polignac number, because 31755421 - 2¹ = 31755419 is a prime.

Together with 31755419, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 31755421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31755481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15877710 + 15877711.

It is an arithmetic number, because the mean of its divisors is an integer number (15877711).

Almost surely, 2^31755421 is an apocalyptic number.

It is an amenable number.

31755421 is a deficient number, since it is larger than the sum of its proper divisors (1).

31755421 is an equidigital number, since it uses as much as digits as its factorization.

31755421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4200, while the sum is 28.

The square root of 31755421 is about 5635.1948502248. The cubic root of 31755421 is about 316.6692972388.

The spelling of 31755421 in words is "thirty-one million, seven hundred fifty-five thousand, four hundred twenty-one".