21470140 has 12 divisors (see below), whose sum is σ = 45087336. Its totient is φ = 8588048.

The previous prime is 21470123. The next prime is 21470149. The reversal of 21470140 is 4107412.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21470149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 536734 + ... + 536773.

It is an arithmetic number, because the mean of its divisors is an integer number (3757278).

Almost surely, 2^21470140 is an apocalyptic number.

21470140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21470140 is an abundant number, since it is smaller than the sum of its proper divisors (23617196).

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

21470140 is a wasteful number, since it uses less digits than its factorization.

21470140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073516 (or 1073514 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 19.

The square root of 21470140 is about 4633.5882423884. The cubic root of 21470140 is about 277.9360997310.

Adding to 21470140 its reverse (4107412), we get a palindrome (25577552).

The spelling of 21470140 in words is "twenty-one million, four hundred seventy thousand, one hundred forty".