31723421 has 2 divisors, whose sum is σ = 31723422. Its totient is φ = 31723420.

The previous prime is 31723409. The next prime is 31723453. The reversal of 31723421 is 12432713.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31483321 + 240100 = 5611^2 + 490^2 .

It is an emirp because it is prime and its reverse (12432713) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31723421 - 2⁶ = 31723357 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31723481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15861710 + 15861711.

It is an arithmetic number, because the mean of its divisors is an integer number (15861711).

Almost surely, 2^31723421 is an apocalyptic number.

It is an amenable number.

31723421 is a deficient number, since it is larger than the sum of its proper divisors (1).

31723421 is an equidigital number, since it uses as much as digits as its factorization.

31723421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 23.

The square root of 31723421 is about 5632.3548361232. The cubic root of 31723421 is about 316.5628920654.

The spelling of 31723421 in words is "thirty-one million, seven hundred twenty-three thousand, four hundred twenty-one".