21980550 has 96 divisors (see below), whose sum is σ = 58567680. Its totient is φ = 5443200.

The previous prime is 21980513. The next prime is 21980561. The reversal of 21980550 is 5508912.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 134769 + ... + 134931.

It is an arithmetic number, because the mean of its divisors is an integer number (610080).

Almost surely, 2^21980550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21980550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29283840).

21980550 is an abundant number, since it is smaller than the sum of its proper divisors (36587130).

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

21980550 is a wasteful number, since it uses less digits than its factorization.

21980550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238 (or 233 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 30.

The square root of 21980550 is about 4688.3419243908. The cubic root of 21980550 is about 280.1213334689.

The spelling of 21980550 in words is "twenty-one million, nine hundred eighty thousand, five hundred fifty".