21421500245 has 4 divisors (see below), whose sum is σ = 25705800300. Its totient is φ = 17137200192.

The previous prime is 21421500227. The next prime is 21421500251. The reversal of 21421500245 is 54200512412.

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 16094981956 + 5326518289 = 126866^2 + 72983^2 .

It is a cyclic number.

It is not a de Polignac number, because 21421500245 - 2⁶ = 21421500181 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2142150020 + ... + 2142150029.

It is an arithmetic number, because the mean of its divisors is an integer number (6426450075).

Almost surely, 2^21421500245 is an apocalyptic number.

It is an amenable number.

21421500245 is a deficient number, since it is larger than the sum of its proper divisors (4284300055).

21421500245 is an equidigital number, since it uses as much as digits as its factorization.

21421500245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4284300054.

The product of its (nonzero) digits is 3200, while the sum is 26.

The spelling of 21421500245 in words is "twenty-one billion, four hundred twenty-one million, five hundred thousand, two hundred forty-five".