20671540 has 24 divisors (see below), whose sum is σ = 44335872. Its totient is φ = 8092320.

The previous prime is 20671531. The next prime is 20671543. The reversal of 20671540 is 4517602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20671543) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 10056 + ... + 11935.

It is an arithmetic number, because the mean of its divisors is an integer number (1847328).

Almost surely, 2^20671540 is an apocalyptic number.

20671540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20671540 is an abundant number, since it is smaller than the sum of its proper divisors (23664332).

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

20671540 is a wasteful number, since it uses less digits than its factorization.

20671540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22047 (or 22045 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 20671540 is about 4546.5965292733. The cubic root of 20671540 is about 274.4464457132.

The spelling of 20671540 in words is "twenty million, six hundred seventy-one thousand, five hundred forty".