231021421 has 4 divisors (see below), whose sum is σ = 234186172. Its totient is φ = 227856672.

The previous prime is 231021419. The next prime is 231021431. The reversal of 231021421 is 124120132.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 64224196 + 166797225 = 8014^2 + 12915^2 .

It is a cyclic number.

It is not a de Polignac number, because 231021421 - 2¹ = 231021419 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 231021395 and 231021404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231021431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1582266 + ... + 1582411.

It is an arithmetic number, because the mean of its divisors is an integer number (58546543).

Almost surely, 2^231021421 is an apocalyptic number.

It is an amenable number.

231021421 is a deficient number, since it is larger than the sum of its proper divisors (3164751).

231021421 is an equidigital number, since it uses as much as digits as its factorization.

231021421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3164750.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 231021421 is about 15199.3888363973. The cubic root of 231021421 is about 613.5982094420.

Adding to 231021421 its reverse (124120132), we get a palindrome (355141553).

The spelling of 231021421 in words is "two hundred thirty-one million, twenty-one thousand, four hundred twenty-one".