21042051445 has 4 divisors (see below), whose sum is σ = 25250461740. Its totient is φ = 16833641152.

The previous prime is 21042051421. The next prime is 21042051451. The reversal of 21042051445 is 54415024012.

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 14920866801 + 6121184644 = 122151^2 + 78238^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21042051445 is a prime.

It is a congruent 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, 2104205140 + ... + 2104205149.

It is an arithmetic number, because the mean of its divisors is an integer number (6312615435).

Almost surely, 2^21042051445 is an apocalyptic number.

It is an amenable number.

21042051445 is a deficient number, since it is larger than the sum of its proper divisors (4208410295).

21042051445 is an equidigital number, since it uses as much as digits as its factorization.

21042051445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4208410294.

The product of its (nonzero) digits is 6400, while the sum is 28.

Adding to 21042051445 its reverse (54415024012), we get a palindrome (75457075457).

The spelling of 21042051445 in words is "twenty-one billion, forty-two million, fifty-one thousand, four hundred forty-five".