21035451505 has 4 divisors (see below), whose sum is σ = 25242541812. Its totient is φ = 16828361200.

The previous prime is 21035451499. The next prime is 21035451509. The reversal of 21035451505 is 50515453012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10581002496 + 10454449009 = 102864^2 + 102247^2 .

It is not a de Polignac number, because 21035451505 - 2⁹ = 21035450993 is a prime.

It is a Smith number, since the sum of its digits (31) 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 not an unprimeable number, because it can be changed into a prime (21035451509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2103545146 + ... + 2103545155.

It is an arithmetic number, because the mean of its divisors is an integer number (6310635453).

Almost surely, 2^21035451505 is an apocalyptic number.

It is an amenable number.

21035451505 is a deficient number, since it is larger than the sum of its proper divisors (4207090307).

21035451505 is an equidigital number, since it uses as much as digits as its factorization.

21035451505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4207090306.

The product of its (nonzero) digits is 15000, while the sum is 31.

The spelling of 21035451505 in words is "twenty-one billion, thirty-five million, four hundred fifty-one thousand, five hundred five".