21249099 has 12 divisors (see below), whose sum is σ = 32498856. Its totient is φ = 13332672.

The previous prime is 21249097. The next prime is 21249101. The reversal of 21249099 is 99094212.

It is an interprime number because it is at equal distance from previous prime (21249097) and next prime (21249101).

It is not a de Polignac number, because 21249099 - 2¹ = 21249097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21249097) 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 11 ways as a sum of consecutive naturals, for example, 69289 + ... + 69594.

It is an arithmetic number, because the mean of its divisors is an integer number (2708238).

Almost surely, 2^21249099 is an apocalyptic number.

21249099 is a deficient number, since it is larger than the sum of its proper divisors (11249757).

21249099 is a wasteful number, since it uses less digits than its factorization.

21249099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138906 (or 138903 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 21249099 is about 4609.6745004393. The cubic root of 21249099 is about 276.9789980906.

The spelling of 21249099 in words is "twenty-one million, two hundred forty-nine thousand, ninety-nine".