21487671691 has 8 divisors (see below), whose sum is σ = 22928447120. Its totient is φ = 20077880832.

The previous prime is 21487671677. The next prime is 21487671697. The reversal of 21487671691 is 19617678412.

It is a happy number.

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 21487671691 - 2⁵ = 21487671659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21487671697) 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, 7744710 + ... + 7747483.

It is an arithmetic number, because the mean of its divisors is an integer number (2866055890).

Almost surely, 2^21487671691 is an apocalyptic number.

21487671691 is a deficient number, since it is larger than the sum of its proper divisors (1440775429).

21487671691 is a wasteful number, since it uses less digits than its factorization.

21487671691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15492285.

The product of its digits is 1016064, while the sum is 52.

The spelling of 21487671691 in words is "twenty-one billion, four hundred eighty-seven million, six hundred seventy-one thousand, six hundred ninety-one".