21387158542 has 4 divisors (see below), whose sum is σ = 32080737816. Its totient is φ = 10693579270.

The previous prime is 21387158531. The next prime is 21387158563. The reversal of 21387158542 is 24585178312.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 21387158492 and 21387158501.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5346789634 + ... + 5346789637.

It is an arithmetic number, because the mean of its divisors is an integer number (8020184454).

Almost surely, 2^21387158542 is an apocalyptic number.

21387158542 is a deficient number, since it is larger than the sum of its proper divisors (10693579274).

21387158542 is a wasteful number, since it uses less digits than its factorization.

21387158542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10693579273.

The product of its digits is 537600, while the sum is 46.

The spelling of 21387158542 in words is "twenty-one billion, three hundred eighty-seven million, one hundred fifty-eight thousand, five hundred forty-two".