21253421560306 has 8 divisors (see below), whose sum is σ = 34332450212844. Its totient is φ = 9809271489360.

The previous prime is 21253421560253. The next prime is 21253421560411. The reversal of 21253421560306 is 60306512435212.

It can be written as a sum of positive squares in 2 ways, for example, as 21049826584081 + 203594976225 = 4588009^2 + 451215^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

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, 408719645365 + ... + 408719645416.

Almost surely, 2^{21253421560306} is an apocalyptic number.

21253421560306 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21253421560306 is a deficient number, since it is larger than the sum of its proper divisors (13079028652538).

21253421560306 is a wasteful number, since it uses less digits than its factorization.

21253421560306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817439290796.

The product of its (nonzero) digits is 259200, while the sum is 40.

Adding to 21253421560306 its reverse (60306512435212), we get a palindrome (81559933995518).

The spelling of 21253421560306 in words is "twenty-one trillion, two hundred fifty-three billion, four hundred twenty-one million, five hundred sixty thousand, three hundred six".