21249001 has 4 divisors (see below), whose sum is σ = 21344512. Its totient is φ = 21153492.

The previous prime is 21248977. The next prime is 21249047. The reversal of 21249001 is 10094212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21249001 - 2²¹ = 19151849 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21249001.

It is not an unprimeable number, because it can be changed into a prime (21249101) 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 3 ways as a sum of consecutive naturals, for example, 47421 + ... + 47866.

It is an arithmetic number, because the mean of its divisors is an integer number (5336128).

Almost surely, 2^21249001 is an apocalyptic number.

It is an amenable number.

21249001 is a deficient number, since it is larger than the sum of its proper divisors (95511).

21249001 is an equidigital number, since it uses as much as digits as its factorization.

21249001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95510.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 21249001 is about 4609.6638706092. The cubic root of 21249001 is about 276.9785722845.

The spelling of 21249001 in words is "twenty-one million, two hundred forty-nine thousand, one".