21320747 has 16 divisors (see below), whose sum is σ = 25623552. Its totient is φ = 17344800.

The previous prime is 21320743. The next prime is 21320749. The reversal of 21320747 is 74702312.

It is a cyclic number.

It is not a de Polignac number, because 21320747 - 2² = 21320743 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21320743) 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, 23873 + ... + 24749.

It is an arithmetic number, because the mean of its divisors is an integer number (1601472).

Almost surely, 2^21320747 is an apocalyptic number.

21320747 is a deficient number, since it is larger than the sum of its proper divisors (4302805).

21320747 is a wasteful number, since it uses less digits than its factorization.

21320747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1058.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 21320747 is about 4617.4394419418. The cubic root of 21320747 is about 277.2899560345.

The spelling of 21320747 in words is "twenty-one million, three hundred twenty thousand, seven hundred forty-seven".