20309719 has 4 divisors (see below), whose sum is σ = 20805120. Its totient is φ = 19814320.

The previous prime is 20309701. The next prime is 20309749. The reversal of 20309719 is 91790302.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20309719 - 2⁷ = 20309591 is a prime.

It is a super-2 number, since 2×20309719² = 824969371717922, 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 (20309749) 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, 247639 + ... + 247720.

It is an arithmetic number, because the mean of its divisors is an integer number (5201280).

Almost surely, 2^20309719 is an apocalyptic number.

20309719 is a deficient number, since it is larger than the sum of its proper divisors (495401).

20309719 is an equidigital number, since it uses as much as digits as its factorization.

20309719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495400.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 20309719 is about 4506.6305595201. The cubic root of 20309719 is about 272.8357682437.

The spelling of 20309719 in words is "twenty million, three hundred nine thousand, seven hundred nineteen".