21031950 has 48 divisors (see below), whose sum is σ = 53853696. Its totient is φ = 5426400.

The previous prime is 21031909. The next prime is 21031973. The reversal of 21031950 is 5913012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2389 + ... + 6911.

It is an arithmetic number, because the mean of its divisors is an integer number (1121952).

Almost surely, 2^21031950 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21031950, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26926848).

21031950 is an abundant number, since it is smaller than the sum of its proper divisors (32821746).

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

21031950 is a wasteful number, since it uses less digits than its factorization.

21031950 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4569 (or 4564 counting only the distinct ones).

The product of its (nonzero) digits is 270, while the sum is 21.

The square root of 21031950 is about 4586.0604008233. The cubic root of 21031950 is about 276.0322636091.

Adding to 21031950 its reverse (5913012), we get a palindrome (26944962).

The spelling of 21031950 in words is "twenty-one million, thirty-one thousand, nine hundred fifty".