21421010 has 32 divisors (see below), whose sum is σ = 42320880. Its totient is φ = 7757568.

The previous prime is 21420991. The next prime is 21421051. The reversal of 21421010 is 1012412.

It can be written as a sum of positive squares in 8 ways, for example, as 4190209 + 17230801 = 2047^2 + 4151^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21420982 and 21421000.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5336 + ... + 8444.

Almost surely, 2^21421010 is an apocalyptic number.

21421010 is a deficient number, since it is larger than the sum of its proper divisors (20899870).

21421010 is a wasteful number, since it uses less digits than its factorization.

21421010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3182.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21421010 is about 4628.2836991697. The cubic root of 21421010 is about 277.7239379504.

Adding to 21421010 its reverse (1012412), we get a palindrome (22433422).

The spelling of 21421010 in words is "twenty-one million, four hundred twenty-one thousand, ten".