21530572079 has 2 divisors, whose sum is σ = 21530572080. Its totient is φ = 21530572078.

The previous prime is 21530572031. The next prime is 21530572111. The reversal of 21530572079 is 97027503512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21530572079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21530572279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765286039 + 10765286040.

It is an arithmetic number, because the mean of its divisors is an integer number (10765286040).

Almost surely, 2^21530572079 is an apocalyptic number.

21530572079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21530572079 is an equidigital number, since it uses as much as digits as its factorization.

21530572079 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 132300, while the sum is 41.

The spelling of 21530572079 in words is "twenty-one billion, five hundred thirty million, five hundred seventy-two thousand, seventy-nine".