21217754951 has 2 divisors, whose sum is σ = 21217754952. Its totient is φ = 21217754950.

The previous prime is 21217754891. The next prime is 21217754981. The reversal of 21217754951 is 15945771212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21217754951 - 2¹⁰ = 21217753927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21217754981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608877475 + 10608877476.

It is an arithmetic number, because the mean of its divisors is an integer number (10608877476).

Almost surely, 2^21217754951 is an apocalyptic number.

21217754951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21217754951 is an equidigital number, since it uses as much as digits as its factorization.

21217754951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 176400, while the sum is 44.

The spelling of 21217754951 in words is "twenty-one billion, two hundred seventeen million, seven hundred fifty-four thousand, nine hundred fifty-one".