21541423009 has 2 divisors, whose sum is σ = 21541423010. Its totient is φ = 21541423008.

The previous prime is 21541422997. The next prime is 21541423067. The reversal of 21541423009 is 90032414512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16042755600 + 5498667409 = 126660^2 + 74153^2 .

It is a cyclic number.

It is not a de Polignac number, because 21541423009 - 2³¹ = 19393939361 is a prime.

It is a super-2 number, since 2×21541423009² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21541423069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770711504 + 10770711505.

It is an arithmetic number, because the mean of its divisors is an integer number (10770711505).

Almost surely, 2^21541423009 is an apocalyptic number.

It is an amenable number.

21541423009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21541423009 is an equidigital number, since it uses as much as digits as its factorization.

21541423009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 31.

The spelling of 21541423009 in words is "twenty-one billion, five hundred forty-one million, four hundred twenty-three thousand, nine".