231470021 has 4 divisors (see below), whose sum is σ = 232808172. Its totient is φ = 230131872.

The previous prime is 231469993. The next prime is 231470023. The reversal of 231470021 is 120074132.

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 211120900 + 20349121 = 14530^2 + 4511^2 .

It is a cyclic number.

It is not a de Polignac number, because 231470021 - 2⁶ = 231469957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 231469975 and 231470002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231470023) 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, 668816 + ... + 669161.

It is an arithmetic number, because the mean of its divisors is an integer number (58202043).

Almost surely, 2^231470021 is an apocalyptic number.

It is an amenable number.

231470021 is a deficient number, since it is larger than the sum of its proper divisors (1338151).

231470021 is a wasteful number, since it uses less digits than its factorization.

231470021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1338150.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 231470021 is about 15214.1388517392. The cubic root of 231470021 is about 613.9951166202.

The spelling of 231470021 in words is "two hundred thirty-one million, four hundred seventy thousand, twenty-one".