21204347951 has 2 divisors, whose sum is σ = 21204347952. Its totient is φ = 21204347950.

The previous prime is 21204347903. The next prime is 21204347963. The reversal of 21204347951 is 15974340212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21204347951 - 2¹⁰ = 21204346927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21204347971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602173975 + 10602173976.

It is an arithmetic number, because the mean of its divisors is an integer number (10602173976).

Almost surely, 2^21204347951 is an apocalyptic number.

21204347951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204347951 is an equidigital number, since it uses as much as digits as its factorization.

21204347951 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 38.

The spelling of 21204347951 in words is "twenty-one billion, two hundred four million, three hundred forty-seven thousand, nine hundred fifty-one".