22491000 has 384 divisors, whose sum is σ = 96033600. Its totient is φ = 4838400.

The previous prime is 22490989. The next prime is 22491013. The reversal of 22491000 is 19422.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1322992 + ... + 1323008.

Almost surely, 2^22491000 is an apocalyptic number.

22491000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22491000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48016800).

22491000 is an abundant number, since it is smaller than the sum of its proper divisors (73542600).

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

22491000 is a wasteful number, since it uses less digits than its factorization.

22491000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61 (or 34 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 22491000 is about 4742.4677120672. The cubic root of 22491000 is about 282.2731622032.

It can be divided in two parts, 2249 and 1000, that added together give a square (3249 = 57²).

The spelling of 22491000 in words is "twenty-two million, four hundred ninety-one thousand".