21421330 has 24 divisors (see below), whose sum is σ = 44854668. Its totient is φ = 7344288.

The previous prime is 21421319. The next prime is 21421333. The reversal of 21421330 is 3312412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19633761 + 1787569 = 4431^2 + 1337^2 .

It is not an unprimeable number, because it can be changed into a prime (21421333) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21369 + ... + 22348.

Almost surely, 2^21421330 is an apocalyptic number.

21421330 is an abundant number, since it is smaller than the sum of its proper divisors (23433338).

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

21421330 is a wasteful number, since it uses less digits than its factorization.

21421330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43738 (or 43731 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21421330 is about 4628.3182690908. The cubic root of 21421330 is about 277.7253208796.

Adding to 21421330 its reverse (3312412), we get a palindrome (24733742).

The spelling of 21421330 in words is "twenty-one million, four hundred twenty-one thousand, three hundred thirty".