21406265519 has 4 divisors (see below), whose sum is σ = 21443365344. Its totient is φ = 21369165696.

The previous prime is 21406265509. The next prime is 21406265521. The reversal of 21406265519 is 91556260412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21406265519 - 2⁸ = 21406265263 is a prime.

It is a super-2 number, since 2×21406265519² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406265509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18549047 + ... + 18550200.

It is an arithmetic number, because the mean of its divisors is an integer number (5360841336).

Almost surely, 2^21406265519 is an apocalyptic number.

21406265519 is a deficient number, since it is larger than the sum of its proper divisors (37099825).

21406265519 is an equidigital number, since it uses as much as digits as its factorization.

21406265519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37099824.

The product of its (nonzero) digits is 129600, while the sum is 41.

The spelling of 21406265519 in words is "twenty-one billion, four hundred six million, two hundred sixty-five thousand, five hundred nineteen".