20406740 has 12 divisors (see below), whose sum is σ = 42854196. Its totient is φ = 8162688.

The previous prime is 20406697. The next prime is 20406767. The reversal of 20406740 is 4760402.

It can be written as a sum of positive squares in 2 ways, for example, as 14394436 + 6012304 = 3794^2 + 2452^2 .

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 510149 + ... + 510188.

It is an arithmetic number, because the mean of its divisors is an integer number (3571183).

Almost surely, 2^20406740 is an apocalyptic number.

20406740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20406740 is an abundant number, since it is smaller than the sum of its proper divisors (22447456).

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

20406740 is a wasteful number, since it uses less digits than its factorization.

20406740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1020346 (or 1020344 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 20406740 is about 4517.3819851768. The cubic root of 20406740 is about 273.2695303521.

The spelling of 20406740 in words is "twenty million, four hundred six thousand, seven hundred forty".