21774984 has 64 divisors (see below), whose sum is σ = 67875840. Its totient is φ = 5655360.

The previous prime is 21774983. The next prime is 21775031. The reversal of 21774984 is 48947712.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21774983) 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, 4044 + ... + 7739.

It is an arithmetic number, because the mean of its divisors is an integer number (1060560).

Almost surely, 2^21774984 is an apocalyptic number.

21774984 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21774984 is an abundant number, since it is smaller than the sum of its proper divisors (46100856).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21774984 is a wasteful number, since it uses less digits than its factorization.

21774984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11810 (or 11806 counting only the distinct ones).

The product of its digits is 112896, while the sum is 42.

The square root of 21774984 is about 4666.3673237327. The cubic root of 21774984 is about 279.2453488570.

The spelling of 21774984 in words is "twenty-one million, seven hundred seventy-four thousand, nine hundred eighty-four".