21651049 has 8 divisors (see below), whose sum is σ = 24893568. Its totient is φ = 18445920.

The previous prime is 21651043. The next prime is 21651101. The reversal of 21651049 is 94015612.

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

It is a cyclic number.

It is not a de Polignac number, because 21651049 - 2⁵ = 21651017 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21651043) 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 7 ways as a sum of consecutive naturals, for example, 8092 + ... + 10429.

It is an arithmetic number, because the mean of its divisors is an integer number (3111696).

Almost surely, 2^21651049 is an apocalyptic number.

It is an amenable number.

21651049 is a deficient number, since it is larger than the sum of its proper divisors (3242519).

21651049 is a wasteful number, since it uses less digits than its factorization.

21651049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18695.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 21651049 is about 4653.0687723265. The cubic root of 21651049 is about 278.7145541341.

The spelling of 21651049 in words is "twenty-one million, six hundred fifty-one thousand, forty-nine".