21581488297 has 2 divisors, whose sum is σ = 21581488298. Its totient is φ = 21581488296.

The previous prime is 21581488267. The next prime is 21581488307. The reversal of 21581488297 is 79288418512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12701064601 + 8880423696 = 112699^2 + 94236^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21581488297 is a prime.

It is a super-2 number, since 2×21581488297² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21581488217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10790744148 + 10790744149.

It is an arithmetic number, because the mean of its divisors is an integer number (10790744149).

Almost surely, 2^21581488297 is an apocalyptic number.

It is an amenable number.

21581488297 is a deficient number, since it is larger than the sum of its proper divisors (1).

21581488297 is an equidigital number, since it uses as much as digits as its factorization.

21581488297 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2580480, while the sum is 55.

The spelling of 21581488297 in words is "twenty-one billion, five hundred eighty-one million, four hundred eighty-eight thousand, two hundred ninety-seven".