21457765419 has 4 divisors (see below), whose sum is σ = 28610353896. Its totient is φ = 14305176944.

The previous prime is 21457765403. The next prime is 21457765421. The reversal of 21457765419 is 91456775412.

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 21457765419 - 2⁴ = 21457765403 is a prime.

It is a super-2 number, since 2×21457765419² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21457763419) 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, 3576294234 + ... + 3576294239.

It is an arithmetic number, because the mean of its divisors is an integer number (7152588474).

Almost surely, 2^21457765419 is an apocalyptic number.

21457765419 is a deficient number, since it is larger than the sum of its proper divisors (7152588477).

21457765419 is an equidigital number, since it uses as much as digits as its factorization.

21457765419 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7152588476.

The product of its digits is 2116800, while the sum is 51.

The spelling of 21457765419 in words is "twenty-one billion, four hundred fifty-seven million, seven hundred sixty-five thousand, four hundred nineteen".