21761140 has 24 divisors (see below), whose sum is σ = 46450152. Its totient is φ = 8561280.

The previous prime is 21761093. The next prime is 21761153. The reversal of 21761140 is 4116712.

It can be written as a sum of positive squares in 4 ways, for example, as 1004004 + 20757136 = 1002^2 + 4556^2 .

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, 7699 + ... + 10138.

It is an arithmetic number, because the mean of its divisors is an integer number (1935423).

Almost surely, 2^21761140 is an apocalyptic number.

21761140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21761140 is an abundant number, since it is smaller than the sum of its proper divisors (24689012).

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

21761140 is a wasteful number, since it uses less digits than its factorization.

21761140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17907 (or 17905 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21761140 is about 4664.8837070178. The cubic root of 21761140 is about 279.1861571996.

Adding to 21761140 its reverse (4116712), we get a palindrome (25877852).

The spelling of 21761140 in words is "twenty-one million, seven hundred sixty-one thousand, one hundred forty".