20447540 has 12 divisors (see below), whose sum is σ = 42939876. Its totient is φ = 8179008.

The previous prime is 20447533. The next prime is 20447543. The reversal of 20447540 is 4574402.

It can be written as a sum of positive squares in 2 ways, for example, as 16096144 + 4351396 = 4012^2 + 2086^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20447543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 511169 + ... + 511208.

It is an arithmetic number, because the mean of its divisors is an integer number (3578323).

Almost surely, 2^20447540 is an apocalyptic number.

20447540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20447540 is an abundant number, since it is smaller than the sum of its proper divisors (22492336).

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

20447540 is a wasteful number, since it uses less digits than its factorization.

20447540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1022386 (or 1022384 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 26.

The square root of 20447540 is about 4521.8956202018. The cubic root of 20447540 is about 273.4515286299.

The spelling of 20447540 in words is "twenty million, four hundred forty-seven thousand, five hundred forty".