20724387 has 8 divisors (see below), whose sum is σ = 27667536. Its totient is φ = 13798752.

The previous prime is 20724371. The next prime is 20724397. The reversal of 20724387 is 78342702.

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

It is not a de Polignac number, because 20724387 - 2⁴ = 20724371 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20724367) 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, 1308 + ... + 6569.

It is an arithmetic number, because the mean of its divisors is an integer number (3458442).

Almost surely, 2^20724387 is an apocalyptic number.

20724387 is a deficient number, since it is larger than the sum of its proper divisors (6943149).

20724387 is an equidigital number, since it uses as much as digits as its factorization.

20724387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8757.

The product of its (nonzero) digits is 18816, while the sum is 33.

The square root of 20724387 is about 4552.4045294767. The cubic root of 20724387 is about 274.6801217278.

The spelling of 20724387 in words is "twenty million, seven hundred twenty-four thousand, three hundred eighty-seven".