21276810643 has 8 divisors (see below), whose sum is σ = 23504878080. Its totient is φ = 19097711880.

The previous prime is 21276810617. The next prime is 21276810647. The reversal of 21276810643 is 34601867212.

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 21276810643 - 2¹³ = 21276802451 is a prime.

It is a super-2 number, since 2×21276810643² (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 = 21276810596 and 21276810605.

It is not an unprimeable number, because it can be changed into a prime (21276810647) 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, 12241255 + ... + 12242992.

It is an arithmetic number, because the mean of its divisors is an integer number (2938109760).

Almost surely, 2^21276810643 is an apocalyptic number.

21276810643 is a deficient number, since it is larger than the sum of its proper divisors (2228067437).

21276810643 is a wasteful number, since it uses less digits than its factorization.

21276810643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24484337.

The product of its (nonzero) digits is 96768, while the sum is 40.

The spelling of 21276810643 in words is "twenty-one billion, two hundred seventy-six million, eight hundred ten thousand, six hundred forty-three".