21533010 has 32 divisors (see below), whose sum is σ = 51960960. Its totient is φ = 5710848.

The previous prime is 21533009. The next prime is 21533011. The reversal of 21533010 is 1033512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21533009) and next prime (21533011).

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

It is not an unprimeable number, because it can be changed into a prime (21533011) 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, 3931 + ... + 7649.

It is an arithmetic number, because the mean of its divisors is an integer number (1623780).

Almost surely, 2^21533010 is an apocalyptic number.

21533010 is an abundant number, since it is smaller than the sum of its proper divisors (30427950).

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

21533010 is a wasteful number, since it uses less digits than its factorization.

21533010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3922.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 21533010 is about 4640.3674423476. The cubic root of 21533010 is about 278.2071244245.

Adding to 21533010 its reverse (1033512), we get a palindrome (22566522).

The spelling of 21533010 in words is "twenty-one million, five hundred thirty-three thousand, ten".