431921981 has 2 divisors, whose sum is σ = 431921982. Its totient is φ = 431921980.

The previous prime is 431921939. The next prime is 431922031. The reversal of 431921981 is 189129134.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 419881081 + 12040900 = 20491^2 + 3470^2 .

It is a cyclic number.

It is not a de Polignac number, because 431921981 - 2¹⁴ = 431905597 is a prime.

It is a super-2 number, since 2×431921981² = 373113195341928722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (431921081) 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, 215960990 + 215960991.

It is an arithmetic number, because the mean of its divisors is an integer number (215960991).

Almost surely, 2^431921981 is an apocalyptic number.

It is an amenable number.

431921981 is a deficient number, since it is larger than the sum of its proper divisors (1).

431921981 is an equidigital number, since it uses as much as digits as its factorization.

431921981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 38.

The square root of 431921981 is about 20782.7327606357. The cubic root of 431921981 is about 755.9071189654.

The spelling of 431921981 in words is "four hundred thirty-one million, nine hundred twenty-one thousand, nine hundred eighty-one".