21140240 has 40 divisors (see below), whose sum is σ = 53621568. Its totient is φ = 7687040.

The previous prime is 21140239. The next prime is 21140291. The reversal of 21140240 is 4204112.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-3 number, since 3×21140240³ (a number of 23 digits) contains 333 as substring.

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, 11132 + ... + 12891.

Almost surely, 2^21140240 is an apocalyptic number.

21140240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21140240 is an abundant number, since it is smaller than the sum of its proper divisors (32481328).

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

21140240 is a wasteful number, since it uses less digits than its factorization.

21140240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24047 (or 24041 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21140240 is about 4597.8516722487. The cubic root of 21140240 is about 276.5052008609.

Adding to 21140240 its reverse (4204112), we get a palindrome (25344352).

The spelling of 21140240 in words is "twenty-one million, one hundred forty thousand, two hundred forty".