20887540 has 24 divisors (see below), whose sum is σ = 45377640. Its totient is φ = 8066688.

The previous prime is 20887483. The next prime is 20887541. The reversal of 20887540 is 4578802.

It can be written as a sum of positive squares in 4 ways, for example, as 1860496 + 19027044 = 1364^2 + 4362^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20887496 and 20887505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20887541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17427 + ... + 18586.

It is an arithmetic number, because the mean of its divisors is an integer number (1890735).

Almost surely, 2^20887540 is an apocalyptic number.

20887540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20887540 is an abundant number, since it is smaller than the sum of its proper divisors (24490100).

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

20887540 is a wasteful number, since it uses less digits than its factorization.

20887540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36051 (or 36049 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 34.

The square root of 20887540 is about 4570.2888311353. The cubic root of 20887540 is about 275.3990460180.

The spelling of 20887540 in words is "twenty million, eight hundred eighty-seven thousand, five hundred forty".