21978840219 has 16 divisors (see below), whose sum is σ = 33950356992. Its totient is φ = 12387290688.

The previous prime is 21978840211. The next prime is 21978840251. The reversal of 21978840219 is 91204887912.

It is a happy number.

It is not a de Polignac number, because 21978840219 - 2³ = 21978840211 is a prime.

It is a super-2 number, since 2×21978840219² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21978840211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7167039 + ... + 7170104.

It is an arithmetic number, because the mean of its divisors is an integer number (2121897312).

Almost surely, 2^21978840219 is an apocalyptic number.

21978840219 is a deficient number, since it is larger than the sum of its proper divisors (11971516773).

21978840219 is a wasteful number, since it uses less digits than its factorization.

21978840219 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14337226.

The product of its (nonzero) digits is 580608, while the sum is 51.

The spelling of 21978840219 in words is "twenty-one billion, nine hundred seventy-eight million, eight hundred forty thousand, two hundred nineteen".