21203430 has 32 divisors (see below), whose sum is σ = 53568000. Its totient is φ = 5356512.

The previous prime is 21203419. The next prime is 21203431. The reversal of 21203430 is 3430212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203431) 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, 18030 + ... + 19169.

It is an arithmetic number, because the mean of its divisors is an integer number (1674000).

Almost surely, 2^21203430 is an apocalyptic number.

21203430 is an abundant number, since it is smaller than the sum of its proper divisors (32364570).

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

21203430 is a wasteful number, since it uses less digits than its factorization.

21203430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37228.

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21203430 is about 4604.7182324220. The cubic root of 21203430 is about 276.7804261137.

Adding to 21203430 its reverse (3430212), we get a palindrome (24633642).

The spelling of 21203430 in words is "twenty-one million, two hundred three thousand, four hundred thirty".