21525505145 has 8 divisors (see below), whose sum is σ = 27350053704. Its totient is φ = 16207439104.

The previous prime is 21525505091. The next prime is 21525505151. The reversal of 21525505145 is 54150552512.

It can be written as a sum of positive squares in 4 ways, for example, as 9832110649 + 11693394496 = 99157^2 + 108136^2 .

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 21525505145 - 2⁶ = 21525505081 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126620534 + ... + 126620703.

It is an arithmetic number, because the mean of its divisors is an integer number (3418756713).

Almost surely, 2^21525505145 is an apocalyptic number.

It is an amenable number.

21525505145 is a deficient number, since it is larger than the sum of its proper divisors (5824548559).

21525505145 is a wasteful number, since it uses less digits than its factorization.

21525505145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253241259.

The product of its (nonzero) digits is 50000, while the sum is 35.

The spelling of 21525505145 in words is "twenty-one billion, five hundred twenty-five million, five hundred five thousand, one hundred forty-five".