21231430061 has 2 divisors, whose sum is σ = 21231430062. Its totient is φ = 21231430060.

The previous prime is 21231430013. The next prime is 21231430063. The reversal of 21231430061 is 16003413212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18161605225 + 3069824836 = 134765^2 + 55406^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21231430061 is a prime.

Together with 21231430063, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231430063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615715030 + 10615715031.

It is an arithmetic number, because the mean of its divisors is an integer number (10615715031).

Almost surely, 2^21231430061 is an apocalyptic number.

It is an amenable number.

21231430061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231430061 is an equidigital number, since it uses as much as digits as its factorization.

21231430061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 21231430061 its reverse (16003413212), we get a palindrome (37234843273).

The spelling of 21231430061 in words is "twenty-one billion, two hundred thirty-one million, four hundred thirty thousand, sixty-one".