20724581 has 8 divisors (see below), whose sum is σ = 22454784. Its totient is φ = 19051200.

The previous prime is 20724569. The next prime is 20724601. The reversal of 20724581 is 18542702.

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

It is a cyclic number.

It is not a de Polignac number, because 20724581 - 2¹⁰ = 20723557 is a prime.

It is a super-2 number, since 2×20724581² = 859016515251122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20724511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13445 + ... + 14906.

It is an arithmetic number, because the mean of its divisors is an integer number (2806848).

Almost surely, 2^20724581 is an apocalyptic number.

It is an amenable number.

20724581 is a deficient number, since it is larger than the sum of its proper divisors (1730203).

20724581 is a wasteful number, since it uses less digits than its factorization.

20724581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28411.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 20724581 is about 4552.4258368479. The cubic root of 20724581 is about 274.6809788143.

The spelling of 20724581 in words is "twenty million, seven hundred twenty-four thousand, five hundred eighty-one".