21849651 has 12 divisors (see below), whose sum is σ = 32078800. Its totient is φ = 14327280.

The previous prime is 21849643. The next prime is 21849671. The reversal of 21849651 is 15694812.

It is not a de Polignac number, because 21849651 - 2³ = 21849643 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21849631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19351 + ... + 20448.

Almost surely, 2^21849651 is an apocalyptic number.

21849651 is a deficient number, since it is larger than the sum of its proper divisors (10229149).

21849651 is a wasteful number, since it uses less digits than its factorization.

21849651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39866 (or 39863 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 21849651 is about 4674.3610258516. The cubic root of 21849651 is about 279.5641646374.

It can be divided in two parts, 21849 and 651, that added together give a square (22500 = 150²).

The spelling of 21849651 in words is "twenty-one million, eight hundred forty-nine thousand, six hundred fifty-one".