21807459551 has 8 divisors (see below), whose sum is σ = 23053745520. Its totient is φ = 20571026112.

The previous prime is 21807459539. The next prime is 21807459593. The reversal of 21807459551 is 15595470812.

It is a happy number.

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 21807459551 - 2¹⁸ = 21807197407 is a prime.

It is a super-2 number, since 2×21807459551² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21807459496 and 21807459505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21807459251) 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, 2458580 + ... + 2467433.

It is an arithmetic number, because the mean of its divisors is an integer number (2881718190).

Almost surely, 2^21807459551 is an apocalyptic number.

21807459551 is a deficient number, since it is larger than the sum of its proper divisors (1246285969).

21807459551 is a wasteful number, since it uses less digits than its factorization.

21807459551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4926265.

The product of its (nonzero) digits is 504000, while the sum is 47.

The spelling of 21807459551 in words is "twenty-one billion, eight hundred seven million, four hundred fifty-nine thousand, five hundred fifty-one".