20822640 has 80 divisors (see below), whose sum is σ = 65808288. Its totient is φ = 5444608.

The previous prime is 20822591. The next prime is 20822647. The reversal of 20822640 is 4622802.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20822640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20822647) 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, 11902 + ... + 13538.

Almost surely, 2^20822640 is an apocalyptic number.

20822640 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 20822640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32904144).

20822640 is an abundant number, since it is smaller than the sum of its proper divisors (44985648).

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

20822640 is a wasteful number, since it uses less digits than its factorization.

20822640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706 (or 1700 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 20822640 is about 4563.1830995479. The cubic root of 20822640 is about 275.1135178725.

The spelling of 20822640 in words is "twenty million, eight hundred twenty-two thousand, six hundred forty".