21542104669 has 2 divisors, whose sum is σ = 21542104670. Its totient is φ = 21542104668.

The previous prime is 21542104621. The next prime is 21542104699. The reversal of 21542104669 is 96640124512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21014851225 + 527253444 = 144965^2 + 22962^2 .

It is a cyclic number.

It is not a de Polignac number, because 21542104669 - 2²⁹ = 21005233757 is a prime.

It is a super-2 number, since 2×21542104669² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21542104699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10771052334 + 10771052335.

It is an arithmetic number, because the mean of its divisors is an integer number (10771052335).

Almost surely, 2^21542104669 is an apocalyptic number.

It is an amenable number.

21542104669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21542104669 is an equidigital number, since it uses as much as digits as its factorization.

21542104669 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 103680, while the sum is 40.

The spelling of 21542104669 in words is "twenty-one billion, five hundred forty-two million, one hundred four thousand, six hundred sixty-nine".