21061650 has 24 divisors (see below), whose sum is σ = 52233264. Its totient is φ = 5616400.

The previous prime is 21061639. The next prime is 21061669. The reversal of 21061650 is 5616012.

It is a happy number.

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70056 + ... + 70355.

It is an arithmetic number, because the mean of its divisors is an integer number (2176386).

Almost surely, 2^21061650 is an apocalyptic number.

21061650 is an abundant number, since it is smaller than the sum of its proper divisors (31171614).

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

21061650 is a wasteful number, since it uses less digits than its factorization.

21061650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140426 (or 140421 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 21061650 is about 4589.2973318363. The cubic root of 21061650 is about 276.1621343103.

Adding to 21061650 its reverse (5616012), we get a palindrome (26677662).

The spelling of 21061650 in words is "twenty-one million, sixty-one thousand, six hundred fifty".