21987642483742 has 16 divisors (see below), whose sum is σ = 35523495967680. Its totient is φ = 10146715093152.

The previous prime is 21987642483739. The next prime is 21987642483743. The reversal of 21987642483742 is 24738424678912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21987642483743) 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, 59294598 + ... + 59664265.

It is an arithmetic number, because the mean of its divisors is an integer number (2220218497980).

Almost surely, 2^{21987642483742} is an apocalyptic number.

21987642483742 is a deficient number, since it is larger than the sum of its proper divisors (13535853483938).

21987642483742 is a wasteful number, since it uses less digits than its factorization.

21987642483742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118965987.

The product of its digits is 260112384, while the sum is 67.

The spelling of 21987642483742 in words is "twenty-one trillion, nine hundred eighty-seven billion, six hundred forty-two million, four hundred eighty-three thousand, seven hundred forty-two".