21135450 has 48 divisors (see below), whose sum is σ = 59906880. Its totient is φ = 4830720.

The previous prime is 21135449. The next prime is 21135451. The reversal of 21135450 is 5453112.

It is an interprime number because it is at equal distance from previous prime (21135449) and next prime (21135451).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a zygodrome in base 4.

It is not an unprimeable number, because it can be changed into a prime (21135451) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9015 + ... + 11114.

It is an arithmetic number, because the mean of its divisors is an integer number (1248060).

Almost surely, 2^21135450 is an apocalyptic number.

21135450 is an abundant number, since it is smaller than the sum of its proper divisors (38771430).

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

21135450 is a wasteful number, since it uses less digits than its factorization.

21135450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20151 (or 20146 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 21135450 is about 4597.3307472924. The cubic root of 21135450 is about 276.4843155736.

Adding to 21135450 its reverse (5453112), we get a palindrome (26588562).

The spelling of 21135450 in words is "twenty-one million, one hundred thirty-five thousand, four hundred fifty".