21025205045 has 32 divisors (see below), whose sum is σ = 27924650208. Its totient is φ = 15096250368.

The previous prime is 21025205023. The next prime is 21025205081. The reversal of 21025205045 is 54050252012.

It can be written as a sum of positive squares in 16 ways, for example, as 4441689316 + 16583515729 = 66646^2 + 128777^2 .

It is a cyclic number.

It is not a de Polignac number, because 21025205045 - 2¹² = 21025200949 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5811077 + ... + 5814693.

It is an arithmetic number, because the mean of its divisors is an integer number (872645319).

Almost surely, 2^21025205045 is an apocalyptic number.

It is an amenable number.

21025205045 is a deficient number, since it is larger than the sum of its proper divisors (6899445163).

21025205045 is a wasteful number, since it uses less digits than its factorization.

21025205045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6089.

The product of its (nonzero) digits is 4000, while the sum is 26.

Adding to 21025205045 its reverse (54050252012), we get a palindrome (75075457057).

The spelling of 21025205045 in words is "twenty-one billion, twenty-five million, two hundred five thousand, forty-five".