21980216 has 8 divisors (see below), whose sum is σ = 41212920. Its totient is φ = 10990104.

The previous prime is 21980197. The next prime is 21980243. The reversal of 21980216 is 61208912.

It is a tau number, because it is divible by the number of its divisors (8).

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, 1373756 + ... + 1373771.

It is an arithmetic number, because the mean of its divisors is an integer number (5151615).

Almost surely, 2^21980216 is an apocalyptic number.

It is an amenable number.

21980216 is a deficient number, since it is larger than the sum of its proper divisors (19232704).

21980216 is a wasteful number, since it uses less digits than its factorization.

21980216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2747533 (or 2747529 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 21980216 is about 4688.3063039865. The cubic root of 21980216 is about 280.1199146236.

The spelling of 21980216 in words is "twenty-one million, nine hundred eighty thousand, two hundred sixteen".