21060621 has 16 divisors (see below), whose sum is σ = 31513920. Its totient is φ = 13899600.

The previous prime is 21060619. The next prime is 21060623. The reversal of 21060621 is 12606012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21060619) and next prime (21060623).

It is not a de Polignac number, because 21060621 - 2¹ = 21060619 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21060594 and 21060603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21060623) 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, 1135 + ... + 6588.

It is an arithmetic number, because the mean of its divisors is an integer number (1969620).

Almost surely, 2^21060621 is an apocalyptic number.

It is an amenable number.

21060621 is a deficient number, since it is larger than the sum of its proper divisors (10453299).

21060621 is a wasteful number, since it uses less digits than its factorization.

21060621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7833 (or 7827 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 21060621 is about 4589.1852218014. The cubic root of 21060621 is about 276.1576367921.

Adding to 21060621 its reverse (12606012), we get a palindrome (33666633).

The spelling of 21060621 in words is "twenty-one million, sixty thousand, six hundred twenty-one".