21284917069 has 4 divisors (see below), whose sum is σ = 22922218396. Its totient is φ = 19647615744.

The previous prime is 21284917033. The next prime is 21284917081. The reversal of 21284917069 is 96071948212.

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 5721107044 + 15563810025 = 75638^2 + 124755^2 .

It is a cyclic number.

It is not a de Polignac number, because 21284917069 - 2⁷ = 21284916941 is a prime.

It is a super-2 number, since 2×21284917069² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21284917469) by changing a digit.

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, 818650644 + ... + 818650669.

It is an arithmetic number, because the mean of its divisors is an integer number (5730554599).

Almost surely, 2^21284917069 is an apocalyptic number.

It is an amenable number.

21284917069 is a deficient number, since it is larger than the sum of its proper divisors (1637301327).

21284917069 is a wasteful number, since it uses less digits than its factorization.

21284917069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1637301326.

The product of its (nonzero) digits is 435456, while the sum is 49.

The spelling of 21284917069 in words is "twenty-one billion, two hundred eighty-four million, nine hundred seventeen thousand, sixty-nine".