21797421842 has 32 divisors (see below), whose sum is σ = 37475996544. Its totient is φ = 9314553600.

The previous prime is 21797421827. The next prime is 21797421869. The reversal of 21797421842 is 24812479712.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9039617 + ... + 9042027.

It is an arithmetic number, because the mean of its divisors is an integer number (1171124892).

Almost surely, 2^21797421842 is an apocalyptic number.

21797421842 is a deficient number, since it is larger than the sum of its proper divisors (15678574702).

21797421842 is a wasteful number, since it uses less digits than its factorization.

21797421842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4034.

The product of its digits is 451584, while the sum is 47.

The spelling of 21797421842 in words is "twenty-one billion, seven hundred ninety-seven million, four hundred twenty-one thousand, eight hundred forty-two".