21589967738 has 8 divisors (see below), whose sum is σ = 32386943988. Its totient is φ = 10794319744.

The previous prime is 21589967689. The next prime is 21589967741. The reversal of 21589967738 is 83776998512.

It can be written as a sum of positive squares in 2 ways, for example, as 21399886369 + 190081369 = 146287^2 + 13787^2 .

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

It is a super-2 number, since 2×21589967738² (a number of 21 digits) contains 22 as substring.

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, 290381 + ... + 357072.

Almost surely, 2^21589967738 is an apocalyptic number.

21589967738 is a deficient number, since it is larger than the sum of its proper divisors (10796976250).

21589967738 is a wasteful number, since it uses less digits than its factorization.

21589967738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664128.

The product of its digits is 45722880, while the sum is 65.

The spelling of 21589967738 in words is "twenty-one billion, five hundred eighty-nine million, nine hundred sixty-seven thousand, seven hundred thirty-eight".