21421064 has 16 divisors (see below), whose sum is σ = 45902400. Its totient is φ = 9180432.

The previous prime is 21421061. The next prime is 21421091. The reversal of 21421064 is 46012412.

It is not an unprimeable number, because it can be changed into a prime (21421061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 191204 + ... + 191315.

It is an arithmetic number, because the mean of its divisors is an integer number (2868900).

Almost surely, 2^21421064 is an apocalyptic number.

It is an amenable number.

21421064 is an abundant number, since it is smaller than the sum of its proper divisors (24481336).

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

21421064 is a wasteful number, since it uses less digits than its factorization.

21421064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382532 (or 382528 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 21421064 is about 4628.2895328620. The cubic root of 21421064 is about 277.7241713207.

Adding to 21421064 its reverse (46012412), we get a palindrome (67433476).

The spelling of 21421064 in words is "twenty-one million, four hundred twenty-one thousand, sixty-four".