21142040 has 32 divisors (see below), whose sum is σ = 47828880. Its totient is φ = 8410752.

The previous prime is 21142021. The next prime is 21142061. The reversal of 21142040 is 4024112.

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, 6539 + ... + 9221.

Almost surely, 2^21142040 is an apocalyptic number.

21142040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21142040 is an abundant number, since it is smaller than the sum of its proper divisors (26686840).

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

21142040 is a wasteful number, since it uses less digits than its factorization.

21142040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2891 (or 2887 counting only the distinct ones).

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

The square root of 21142040 is about 4598.0474116738. The cubic root of 21142040 is about 276.5130483789.

Adding to 21142040 its reverse (4024112), we get a palindrome (25166152).

The spelling of 21142040 in words is "twenty-one million, one hundred forty-two thousand, forty".