21217577450 has 24 divisors (see below), whose sum is σ = 40209315948. Its totient is φ = 8326897280.

The previous prime is 21217577417. The next prime is 21217577477. The reversal of 21217577450 is 5477571212.

It can be written as a sum of positive squares in 6 ways, for example, as 5490661801 + 15726915649 = 74099^2 + 125407^2 .

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21217577398 and 21217577407.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4000667 + ... + 4005966.

Almost surely, 2^21217577450 is an apocalyptic number.

21217577450 is a deficient number, since it is larger than the sum of its proper divisors (18991738498).

21217577450 is a wasteful number, since it uses less digits than its factorization.

21217577450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8006698 (or 8006693 counting only the distinct ones).

The product of its (nonzero) digits is 137200, while the sum is 41.

The spelling of 21217577450 in words is "twenty-one billion, two hundred seventeen million, five hundred seventy-seven thousand, four hundred fifty".