21805012654 has 8 divisors (see below), whose sum is σ = 32745686688. Its totient is φ = 10889783760.

The previous prime is 21805012643. The next prime is 21805012703. The reversal of 21805012654 is 45621050812.

It is a happy number.

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

It is a super-2 number, since 2×21805012654² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6359142 + ... + 6362569.

It is an arithmetic number, because the mean of its divisors is an integer number (4093210836).

Almost surely, 2^21805012654 is an apocalyptic number.

21805012654 is a deficient number, since it is larger than the sum of its proper divisors (10940674034).

21805012654 is a wasteful number, since it uses less digits than its factorization.

21805012654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12722570.

The product of its (nonzero) digits is 19200, while the sum is 34.

The spelling of 21805012654 in words is "twenty-one billion, eight hundred five million, twelve thousand, six hundred fifty-four".