21627649 has 8 divisors (see below), whose sum is σ = 22449960. Its totient is φ = 20810496.

The previous prime is 21627629. The next prime is 21627679. The reversal of 21627649 is 94672612.

It can be written as a sum of positive squares in 4 ways, for example, as 7617600 + 14010049 = 2760^2 + 3743^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21627649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21627629) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 8667 + ... + 10879.

It is an arithmetic number, because the mean of its divisors is an integer number (2806245).

Almost surely, 2^21627649 is an apocalyptic number.

21627649 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21627649 is a deficient number, since it is larger than the sum of its proper divisors (822311).

21627649 is a wasteful number, since it uses less digits than its factorization.

21627649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2579.

The product of its digits is 36288, while the sum is 37.

The square root of 21627649 is about 4650.5536229572. The cubic root of 21627649 is about 278.6141083225.

The spelling of 21627649 in words is "twenty-one million, six hundred twenty-seven thousand, six hundred forty-nine".