21605246452 has 12 divisors (see below), whose sum is σ = 37812697636. Its totient is φ = 10801618560.

The previous prime is 21605246449. The next prime is 21605246483. The reversal of 21605246452 is 25464250612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4372383376 + 17232863076 = 66124^2 + 131274^2 .

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, 201699 + ... + 289642.

Almost surely, 2^21605246452 is an apocalyptic number.

It is an amenable number.

21605246452 is a deficient number, since it is larger than the sum of its proper divisors (16207451184).

21605246452 is a wasteful number, since it uses less digits than its factorization.

21605246452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502338 (or 502336 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 37.

The spelling of 21605246452 in words is "twenty-one billion, six hundred five million, two hundred forty-six thousand, four hundred fifty-two".