21440130 has 32 divisors (see below), whose sum is σ = 52714368. Its totient is φ = 5577600.

The previous prime is 21440129. The next prime is 21440137. The reversal of 21440130 is 3104412.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21440137) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7486 + ... + 9945.

It is an arithmetic number, because the mean of its divisors is an integer number (1647324).

Almost surely, 2^21440130 is an apocalyptic number.

21440130 is an abundant number, since it is smaller than the sum of its proper divisors (31274238).

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

21440130 is a wasteful number, since it uses less digits than its factorization.

21440130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17482.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21440130 is about 4630.3487989567. The cubic root of 21440130 is about 277.8065438061.

Adding to 21440130 its reverse (3104412), we get a palindrome (24544542).

The spelling of 21440130 in words is "twenty-one million, four hundred forty thousand, one hundred thirty".