21797190 has 48 divisors (see below), whose sum is σ = 57889728. Its totient is φ = 5687808.

The previous prime is 21797189. The next prime is 21797197. The reversal of 21797190 is 9179712.

It is a super-2 number, since 2×21797190² = 950234983792200, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21797197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1654 + ... + 6806.

It is an arithmetic number, because the mean of its divisors is an integer number (1206036).

Almost surely, 2^21797190 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21797190, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28944864).

21797190 is an abundant number, since it is smaller than the sum of its proper divisors (36092538).

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

21797190 is a wasteful number, since it uses less digits than its factorization.

21797190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5213 (or 5210 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 36.

The square root of 21797190 is about 4668.7460843357. The cubic root of 21797190 is about 279.3402408597.

The spelling of 21797190 in words is "twenty-one million, seven hundred ninety-seven thousand, one hundred ninety".