231394128421 has 2 divisors, whose sum is σ = 231394128422. Its totient is φ = 231394128420.

The previous prime is 231394128409. The next prime is 231394128437. The reversal of 231394128421 is 124821493132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154048400100 + 77345728321 = 392490^2 + 278111^2 .

It is a cyclic number.

It is not a de Polignac number, because 231394128421 - 2¹¹ = 231394126373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231394128481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115697064210 + 115697064211.

It is an arithmetic number, because the mean of its divisors is an integer number (115697064211).

Almost surely, 2^231394128421 is an apocalyptic number.

It is an amenable number.

231394128421 is a deficient number, since it is larger than the sum of its proper divisors (1).

231394128421 is an equidigital number, since it uses as much as digits as its factorization.

231394128421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 40.

The spelling of 231394128421 in words is "two hundred thirty-one billion, three hundred ninety-four million, one hundred twenty-eight thousand, four hundred twenty-one".