21611472989 has 8 divisors (see below), whose sum is σ = 22896063288. Its totient is φ = 20328363520.

The previous prime is 21611472979. The next prime is 21611473063. The reversal of 21611472989 is 98927411612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8221048900 + 13390424089 = 90670^2 + 115717^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21611472989 - 2³² = 17316505693 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21611472919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 340082 + ... + 398595.

It is an arithmetic number, because the mean of its divisors is an integer number (2862007911).

Almost surely, 2^21611472989 is an apocalyptic number.

It is an amenable number.

21611472989 is a deficient number, since it is larger than the sum of its proper divisors (1284590299).

21611472989 is a wasteful number, since it uses less digits than its factorization.

21611472989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 740415.

The product of its digits is 435456, while the sum is 50.

The spelling of 21611472989 in words is "twenty-one billion, six hundred eleven million, four hundred seventy-two thousand, nine hundred eighty-nine".