21201205951 has 2 divisors, whose sum is σ = 21201205952. Its totient is φ = 21201205950.

The previous prime is 21201205919. The next prime is 21201205957. The reversal of 21201205951 is 15950210212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21201205951 - 2⁵ = 21201205919 is a prime.

It is a super-2 number, since 2×21201205951² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201205957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600602975 + 10600602976.

It is an arithmetic number, because the mean of its divisors is an integer number (10600602976).

Almost surely, 2^21201205951 is an apocalyptic number.

21201205951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201205951 is an equidigital number, since it uses as much as digits as its factorization.

21201205951 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 28.

The spelling of 21201205951 in words is "twenty-one billion, two hundred one million, two hundred five thousand, nine hundred fifty-one".