21036253805 has 8 divisors (see below), whose sum is σ = 28849719552. Its totient is φ = 14424859728.

The previous prime is 21036253793. The next prime is 21036253817. The reversal of 21036253805 is 50835263012.

It is an interprime number because it is at equal distance from previous prime (21036253793) and next prime (21036253817).

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 21036253805 - 2⁶ = 21036253741 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35), and also a Moran number because the ratio is a prime number: 601035823 = 21036253805 / (2 + 1 + 0 + 3 + 6 + 2 + 5 + 3 + 8 + 0 + 5).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 300517877 + ... + 300517946.

It is an arithmetic number, because the mean of its divisors is an integer number (3606214944).

Almost surely, 2^21036253805 is an apocalyptic number.

It is an amenable number.

21036253805 is a deficient number, since it is larger than the sum of its proper divisors (7813465747).

21036253805 is an equidigital number, since it uses as much as digits as its factorization.

21036253805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 601035835.

The product of its (nonzero) digits is 43200, while the sum is 35.

The spelling of 21036253805 in words is "twenty-one billion, thirty-six million, two hundred fifty-three thousand, eight hundred five".