21216351120542 has 4 divisors (see below), whose sum is σ = 31824526680816. Its totient is φ = 10608175560270.

The previous prime is 21216351120539. The next prime is 21216351120589. The reversal of 21216351120542 is 24502115361212.

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

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, 5304087780134 + ... + 5304087780137.

It is an arithmetic number, because the mean of its divisors is an integer number (7956131670204).

Almost surely, 2^{21216351120542} is an apocalyptic number.

21216351120542 is a deficient number, since it is larger than the sum of its proper divisors (10608175560274).

21216351120542 is a wasteful number, since it uses less digits than its factorization.

21216351120542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10608175560273.

The product of its (nonzero) digits is 28800, while the sum is 35.

Adding to 21216351120542 its reverse (24502115361212), we get a palindrome (45718466481754).

The spelling of 21216351120542 in words is "twenty-one trillion, two hundred sixteen billion, three hundred fifty-one million, one hundred twenty thousand, five hundred forty-two".