21230021999951 has 2 divisors, whose sum is σ = 21230021999952. Its totient is φ = 21230021999950.

The previous prime is 21230021999939. The next prime is 21230022000007. The reversal of 21230021999951 is 15999912003212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21230021999951 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21230021999893 and 21230021999902.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21230021969951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615010999975 + 10615010999976.

It is an arithmetic number, because the mean of its divisors is an integer number (10615010999976).

Almost surely, 2^{21230021999951} is an apocalyptic number.

21230021999951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21230021999951 is an equidigital number, since it uses as much as digits as its factorization.

21230021999951 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 787320, while the sum is 53.

The spelling of 21230021999951 in words is "twenty-one trillion, two hundred thirty billion, twenty-one million, nine hundred ninety-nine thousand, nine hundred fifty-one".