21950 has 12 divisors (see below), whose sum is σ = 40920. Its totient is φ = 8760.

The previous prime is 21943. The next prime is 21961. The reversal of 21950 is 5912.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 170 + ... + 269.

It is an arithmetic number, because the mean of its divisors is an integer number (3410).

2²¹⁹⁵⁰ is an apocalyptic number.

21950 is a deficient number, since it is larger than the sum of its proper divisors (18970).

21950 is a wasteful number, since it uses less digits than its factorization.

21950 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451 (or 446 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 17.

The square root of 21950 is about 148.1553239003. The cubic root of 21950 is about 27.9991496340. Note that the first 3 decimals are identical.

The spelling of 21950 in words is "twenty-one thousand, nine hundred fifty".