21366537835 has 4 divisors (see below), whose sum is σ = 25639845408. Its totient is φ = 17093230264.

The previous prime is 21366537817. The next prime is 21366537859. The reversal of 21366537835 is 53873566312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21366537835 - 2⁷ = 21366537707 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian 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, 2136653779 + ... + 2136653788.

It is an arithmetic number, because the mean of its divisors is an integer number (6409961352).

Almost surely, 2^21366537835 is an apocalyptic number.

21366537835 is a deficient number, since it is larger than the sum of its proper divisors (4273307573).

21366537835 is an equidigital number, since it uses as much as digits as its factorization.

21366537835 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4273307572.

The product of its digits is 2721600, while the sum is 49.

The spelling of 21366537835 in words is "twenty-one billion, three hundred sixty-six million, five hundred thirty-seven thousand, eight hundred thirty-five".