21361311987 has 8 divisors (see below), whose sum is σ = 28483776720. Its totient is φ = 14239860960.

The previous prime is 21361311973. The next prime is 21361312003. The reversal of 21361311987 is 78911316312.

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

It is not a de Polignac number, because 21361311987 - 2⁸ = 21361311731 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21361311947) 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, 202812 + ... + 289577.

It is an arithmetic number, because the mean of its divisors is an integer number (3560472090).

Almost surely, 2^21361311987 is an apocalyptic number.

21361311987 is a deficient number, since it is larger than the sum of its proper divisors (7122464733).

21361311987 is a wasteful number, since it uses less digits than its factorization.

21361311987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506853.

The product of its digits is 54432, while the sum is 42.

The spelling of 21361311987 in words is "twenty-one billion, three hundred sixty-one million, three hundred eleven thousand, nine hundred eighty-seven".