21141240 has 64 divisors (see below), whose sum is σ = 64985760. Its totient is φ = 5498880.

The previous prime is 21141233. The next prime is 21141257. The reversal of 21141240 is 4214112.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2772 + ... + 7068.

Almost surely, 2^21141240 is an apocalyptic number.

21141240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21141240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32492880).

21141240 is an abundant number, since it is smaller than the sum of its proper divisors (43844520).

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

21141240 is a wasteful number, since it uses less digits than its factorization.

21141240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4352 (or 4348 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 21141240 is about 4597.9604174025. The cubic root of 21141240 is about 276.5095606481.

Adding to 21141240 its reverse (4214112), we get a palindrome (25355352).

The spelling of 21141240 in words is "twenty-one million, one hundred forty-one thousand, two hundred forty".