21453778511 has 8 divisors (see below), whose sum is σ = 23611239504. Its totient is φ = 19330837120.

The previous prime is 21453778481. The next prime is 21453778523. The reversal of 21453778511 is 11587735412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21453778511 - 2⁶ = 21453778447 is a prime.

It is a super-2 number, since 2×21453778511² (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 (21453478511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8628596 + ... + 8631081.

It is an arithmetic number, because the mean of its divisors is an integer number (2951404938).

Almost surely, 2^21453778511 is an apocalyptic number.

21453778511 is a deficient number, since it is larger than the sum of its proper divisors (2157460993).

21453778511 is a wasteful number, since it uses less digits than its factorization.

21453778511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17259801.

The product of its digits is 235200, while the sum is 44.

The spelling of 21453778511 in words is "twenty-one billion, four hundred fifty-three million, seven hundred seventy-eight thousand, five hundred eleven".