21304051643 has 8 divisors (see below), whose sum is σ = 24640831488. Its totient is φ = 18040607784.

The previous prime is 21304051627. The next prime is 21304051649. The reversal of 21304051643 is 34615040312.

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 21304051643 - 2⁴ = 21304051627 is a prime.

It is a super-2 number, since 2×21304051643² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21304051649) 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, 18333371 + ... + 18334532.

It is an arithmetic number, because the mean of its divisors is an integer number (3080103936).

Almost surely, 2^21304051643 is an apocalyptic number.

21304051643 is a deficient number, since it is larger than the sum of its proper divisors (3336779845).

21304051643 is an equidigital number, since it uses as much as digits as its factorization.

21304051643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36667993.

The product of its (nonzero) digits is 8640, while the sum is 29.

Adding to 21304051643 its reverse (34615040312), we get a palindrome (55919091955).

The spelling of 21304051643 in words is "twenty-one billion, three hundred four million, fifty-one thousand, six hundred forty-three".