21250649 has 8 divisors (see below), whose sum is σ = 25124160. Its totient is φ = 17586576.

The previous prime is 21250637. The next prime is 21250687. The reversal of 21250649 is 94605212.

It is a happy number.

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

It is not a de Polignac number, because 21250649 - 2⁸ = 21250393 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21250849) 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, 52139 + ... + 52544.

It is an arithmetic number, because the mean of its divisors is an integer number (3140520).

Almost surely, 2^21250649 is an apocalyptic number.

21250649 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21250649 is a deficient number, since it is larger than the sum of its proper divisors (3873511).

21250649 is a wasteful number, since it uses less digits than its factorization.

21250649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104719.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 21250649 is about 4609.8426220425. The cubic root of 21250649 is about 276.9857326037.

The spelling of 21250649 in words is "twenty-one million, two hundred fifty thousand, six hundred forty-nine".