21497829121 has 2 divisors, whose sum is σ = 21497829122. Its totient is φ = 21497829120.

The previous prime is 21497829109. The next prime is 21497829149. The reversal of 21497829121 is 12192879412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15501495025 + 5996334096 = 124505^2 + 77436^2 .

It is a cyclic number.

It is not a de Polignac number, because 21497829121 - 2¹⁷ = 21497698049 is a prime.

It is not a weakly prime, because it can be changed into another prime (21497829161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10748914560 + 10748914561.

It is an arithmetic number, because the mean of its divisors is an integer number (10748914561).

Almost surely, 2^21497829121 is an apocalyptic number.

It is an amenable number.

21497829121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21497829121 is an equidigital number, since it uses as much as digits as its factorization.

21497829121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 46.

The spelling of 21497829121 in words is "twenty-one billion, four hundred ninety-seven million, eight hundred twenty-nine thousand, one hundred twenty-one".