21451139687 has 8 divisors (see below), whose sum is σ = 21731542272. Its totient is φ = 21172217400.

The previous prime is 21451139683. The next prime is 21451139713. The reversal of 21451139687 is 78693115412.

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 21451139687 - 2² = 21451139683 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21451139683) 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, 340889 + ... + 398882.

It is an arithmetic number, because the mean of its divisors is an integer number (2716442784).

Almost surely, 2^21451139687 is an apocalyptic number.

21451139687 is a deficient number, since it is larger than the sum of its proper divisors (280402585).

21451139687 is a wasteful number, since it uses less digits than its factorization.

21451139687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740149.

The product of its digits is 362880, while the sum is 47.

The spelling of 21451139687 in words is "twenty-one billion, four hundred fifty-one million, one hundred thirty-nine thousand, six hundred eighty-seven".