21060646 has 16 divisors (see below), whose sum is σ = 32516784. Its totient is φ = 10226304.

The previous prime is 21060643. The next prime is 21060647. The reversal of 21060646 is 64606012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21060646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21060643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8706 + ... + 10858.

It is an arithmetic number, because the mean of its divisors is an integer number (2032299).

Almost surely, 2^21060646 is an apocalyptic number.

21060646 is a deficient number, since it is larger than the sum of its proper divisors (11456138).

21060646 is a wasteful number, since it uses less digits than its factorization.

21060646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2295.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 21060646 is about 4589.1879455956. The cubic root of 21060646 is about 276.1577460629.

Adding to 21060646 its reverse (64606012), we get a palindrome (85666658).

The spelling of 21060646 in words is "twenty-one million, sixty thousand, six hundred forty-six".