21054340345 has 4 divisors (see below), whose sum is σ = 25265208420. Its totient is φ = 16843472272.

The previous prime is 21054340337. The next prime is 21054340357. The reversal of 21054340345 is 54304345012.

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 3345118569 + 17709221776 = 57837^2 + 133076^2 .

It is a cyclic number.

It is not a de Polignac number, because 21054340345 - 2³ = 21054340337 is a prime.

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, 2105434030 + ... + 2105434039.

It is an arithmetic number, because the mean of its divisors is an integer number (6316302105).

Almost surely, 2^21054340345 is an apocalyptic number.

It is an amenable number.

21054340345 is a deficient number, since it is larger than the sum of its proper divisors (4210868075).

21054340345 is an equidigital number, since it uses as much as digits as its factorization.

21054340345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4210868074.

The product of its (nonzero) digits is 28800, while the sum is 31.

Adding to 21054340345 its reverse (54304345012), we get a palindrome (75358685357).

The spelling of 21054340345 in words is "twenty-one billion, fifty-four million, three hundred forty thousand, three hundred forty-five".