21649137 has 8 divisors (see below), whose sum is σ = 28948704. Its totient is φ = 14391168.

The previous prime is 21649123. The next prime is 21649153. The reversal of 21649137 is 73194612.

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

It is not a de Polignac number, because 21649137 - 2⁶ = 21649073 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21649098 and 21649107.

It is not an unprimeable number, because it can be changed into a prime (21649237) 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, 9163 + ... + 11280.

It is an arithmetic number, because the mean of its divisors is an integer number (3618588).

Almost surely, 2^21649137 is an apocalyptic number.

It is an amenable number.

21649137 is a deficient number, since it is larger than the sum of its proper divisors (7299567).

21649137 is a wasteful number, since it uses less digits than its factorization.

21649137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20799.

The product of its digits is 9072, while the sum is 33.

The square root of 21649137 is about 4652.8633119833. The cubic root of 21649137 is about 278.7063494829.

The spelling of 21649137 in words is "twenty-one million, six hundred forty-nine thousand, one hundred thirty-seven".