21952491409 has 2 divisors, whose sum is σ = 21952491410. Its totient is φ = 21952491408.

The previous prime is 21952491389. The next prime is 21952491437. The reversal of 21952491409 is 90419425912.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13960131409 + 7992360000 = 118153^2 + 89400^2 .

It is a cyclic number.

It is not a de Polignac number, because 21952491409 - 2⁹ = 21952490897 is a prime.

It is not a weakly prime, because it can be changed into another prime (21952492409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10976245704 + 10976245705.

It is an arithmetic number, because the mean of its divisors is an integer number (10976245705).

Almost surely, 2^21952491409 is an apocalyptic number.

It is an amenable number.

21952491409 is a deficient number, since it is larger than the sum of its proper divisors (1).

21952491409 is an equidigital number, since it uses as much as digits as its factorization.

21952491409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 46.

The spelling of 21952491409 in words is "twenty-one billion, nine hundred fifty-two million, four hundred ninety-one thousand, four hundred nine".