20405620 has 24 divisors (see below), whose sum is σ = 45108000. Its totient is φ = 7732512.

The previous prime is 20405579. The next prime is 20405641. The reversal of 20405620 is 2650402.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26470 + ... + 27229.

It is an arithmetic number, because the mean of its divisors is an integer number (1879500).

Almost surely, 2^20405620 is an apocalyptic number.

20405620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20405620 is an abundant number, since it is smaller than the sum of its proper divisors (24702380).

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

20405620 is a wasteful number, since it uses less digits than its factorization.

20405620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53727 (or 53725 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 20405620 is about 4517.2580178688. The cubic root of 20405620 is about 273.2645309014.

It can be divided in two parts, 20405 and 620, that added together give a square (21025 = 145²).

The spelling of 20405620 in words is "twenty million, four hundred five thousand, six hundred twenty".