21414431987 has 4 divisors (see below), whose sum is σ = 23061696000. Its totient is φ = 19767167976.

The previous prime is 21414431977. The next prime is 21414432001. The reversal of 21414431987 is 78913441412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21414431987 - 2³⁰ = 20340690163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21414431977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 823631987 + ... + 823632012.

It is an arithmetic number, because the mean of its divisors is an integer number (5765424000).

Almost surely, 2^21414431987 is an apocalyptic number.

21414431987 is a deficient number, since it is larger than the sum of its proper divisors (1647264013).

21414431987 is a wasteful number, since it uses less digits than its factorization.

21414431987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1647264012.

The product of its digits is 193536, while the sum is 44.

The spelling of 21414431987 in words is "twenty-one billion, four hundred fourteen million, four hundred thirty-one thousand, nine hundred eighty-seven".