21612849 has 16 divisors (see below), whose sum is σ = 29640960. Its totient is φ = 14002560.

The previous prime is 21612841. The next prime is 21612869. The reversal of 21612849 is 94821612.

It is not a de Polignac number, because 21612849 - 2³ = 21612841 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21612841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15624 + ... + 16950.

It is an arithmetic number, because the mean of its divisors is an integer number (1852560).

Almost surely, 2^21612849 is an apocalyptic number.

It is an amenable number.

21612849 is a deficient number, since it is larger than the sum of its proper divisors (8028111).

21612849 is a wasteful number, since it uses less digits than its factorization.

21612849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1480.

The product of its digits is 6912, while the sum is 33.

The square root of 21612849 is about 4648.9621422421. The cubic root of 21612849 is about 278.5505410844.

The spelling of 21612849 in words is "twenty-one million, six hundred twelve thousand, eight hundred forty-nine".