21001330 has 32 divisors (see below), whose sum is σ = 43701120. Its totient is φ = 7117440.

The previous prime is 21001319. The next prime is 21001349. The reversal of 21001330 is 3310012.

It is a Harshad number since it is a multiple of its sum of digits (10).

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, 4545 + ... + 7915.

It is an arithmetic number, because the mean of its divisors is an integer number (1365660).

Almost surely, 2^21001330 is an apocalyptic number.

21001330 is an abundant number, since it is smaller than the sum of its proper divisors (22699790).

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

21001330 is a wasteful number, since it uses less digits than its factorization.

21001330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3474.

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21001330 is about 4582.7208075553. The cubic root of 21001330 is about 275.8982419106.

Adding to 21001330 its reverse (3310012), we get a palindrome (24311342).

The spelling of 21001330 in words is "twenty-one million, one thousand, three hundred thirty".