21951798 has 32 divisors (see below), whose sum is σ = 49980672. Its totient is φ = 6362400.

The previous prime is 21951793. The next prime is 21951803. The reversal of 21951798 is 89715912.

It is an interprime number because it is at equal distance from previous prime (21951793) and next prime (21951803).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21951793) 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, 5713 + ... + 8748.

It is an arithmetic number, because the mean of its divisors is an integer number (1561896).

Almost surely, 2^21951798 is an apocalyptic number.

21951798 is an abundant number, since it is smaller than the sum of its proper divisors (28028874).

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

21951798 is a wasteful number, since it uses less digits than its factorization.

21951798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14500.

The product of its digits is 45360, while the sum is 42.

The square root of 21951798 is about 4685.2745917395. The cubic root of 21951798 is about 279.9991411538. Note that the first 3 decimals are identical.

It can be divided in two parts, 2195 and 1798, that added together give a palindrome (3993).

The spelling of 21951798 in words is "twenty-one million, nine hundred fifty-one thousand, seven hundred ninety-eight".