21221099969 has 2 divisors, whose sum is σ = 21221099970. Its totient is φ = 21221099968.

The previous prime is 21221099953. The next prime is 21221099987. The reversal of 21221099969 is 96999012212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14801885569 + 6419214400 = 121663^2 + 80120^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221099969 - 2⁴ = 21221099953 is a prime.

It is a super-2 number, since 2×21221099969² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21221092969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610549984 + 10610549985.

It is an arithmetic number, because the mean of its divisors is an integer number (10610549985).

Almost surely, 2^21221099969 is an apocalyptic number.

It is an amenable number.

21221099969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221099969 is an equidigital number, since it uses as much as digits as its factorization.

21221099969 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 314928, while the sum is 50.

The spelling of 21221099969 in words is "twenty-one billion, two hundred twenty-one million, ninety-nine thousand, nine hundred sixty-nine".