21821440478 has 4 divisors (see below), whose sum is σ = 32732160720. Its totient is φ = 10910720238.

The previous prime is 21821440477. The next prime is 21821440481. The reversal of 21821440478 is 87404412812.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21821440477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5455360118 + ... + 5455360121.

It is an arithmetic number, because the mean of its divisors is an integer number (8183040180).

Almost surely, 2^21821440478 is an apocalyptic number.

21821440478 is a deficient number, since it is larger than the sum of its proper divisors (10910720242).

21821440478 is a wasteful number, since it uses less digits than its factorization.

21821440478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10910720241.

The product of its (nonzero) digits is 114688, while the sum is 41.

The spelling of 21821440478 in words is "twenty-one billion, eight hundred twenty-one million, four hundred forty thousand, four hundred seventy-eight".