21034505405 has 8 divisors (see below), whose sum is σ = 25274755032. Its totient is φ = 16805371968.

The previous prime is 21034505341. The next prime is 21034505411. The reversal of 21034505405 is 50450543012.

It can be written as a sum of positive squares in 4 ways, for example, as 6713835844 + 14320669561 = 81938^2 + 119669^2 .

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 21034505405 - 2⁶ = 21034505341 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2774882 + ... + 2782451.

It is an arithmetic number, because the mean of its divisors is an integer number (3159344379).

Almost surely, 2^21034505405 is an apocalyptic number.

It is an amenable number.

21034505405 is a deficient number, since it is larger than the sum of its proper divisors (4240249627).

21034505405 is an equidigital number, since it uses as much as digits as its factorization.

21034505405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5558095.

The product of its (nonzero) digits is 12000, while the sum is 29.

The spelling of 21034505405 in words is "twenty-one billion, thirty-four million, five hundred five thousand, four hundred five".