20545440 has 96 divisors (see below), whose sum is σ = 67568256. Its totient is φ = 5237760.

The previous prime is 20545433. The next prime is 20545477. The reversal of 20545440 is 4454502.

It is a tau number, because it is divible by the number of its divisors (96).

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 20545440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10110 + ... + 11970.

It is an arithmetic number, because the mean of its divisors is an integer number (703836).

Almost surely, 2^20545440 is an apocalyptic number.

20545440 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 20545440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33784128).

20545440 is an abundant number, since it is smaller than the sum of its proper divisors (47022816).

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

20545440 is a wasteful number, since it uses less digits than its factorization.

20545440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1902 (or 1894 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 24.

The square root of 20545440 is about 4532.7077999801. The cubic root of 20545440 is about 273.8872500387.

Adding to 20545440 its reverse (4454502), we get a palindrome (24999942).

The spelling of 20545440 in words is "twenty million, five hundred forty-five thousand, four hundred forty".