20413721 has 4 divisors (see below), whose sum is σ = 20428032. Its totient is φ = 20399412.

The previous prime is 20413703. The next prime is 20413739. The reversal of 20413721 is 12731402.

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 an interprime number because it is at equal distance from previous prime (20413703) and next prime (20413739).

It is a cyclic number.

It is not a de Polignac number, because 20413721 - 2¹⁰ = 20412697 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20413693 and 20413702.

It is not an unprimeable number, because it can be changed into a prime (20413021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4745 + ... + 7958.

It is an arithmetic number, because the mean of its divisors is an integer number (5107008).

Almost surely, 2^20413721 is an apocalyptic number.

It is an amenable number.

20413721 is a deficient number, since it is larger than the sum of its proper divisors (14311).

20413721 is a wasteful number, since it uses less digits than its factorization.

20413721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14310.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20413721 is about 4518.1546011619. The cubic root of 20413721 is about 273.3006879843.

The spelling of 20413721 in words is "twenty million, four hundred thirteen thousand, seven hundred twenty-one".