20423691 has 8 divisors (see below), whose sum is σ = 30257360. Its totient is φ = 13615776.

The previous prime is 20423653. The next prime is 20423707. The reversal of 20423691 is 19632402.

It is not a de Polignac number, because 20423691 - 2¹⁷ = 20292619 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 756433 = 20423691 / (2 + 0 + 4 + 2 + 3 + 6 + 9 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20423621) 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, 378190 + ... + 378243.

It is an arithmetic number, because the mean of its divisors is an integer number (3782170).

Almost surely, 2^20423691 is an apocalyptic number.

20423691 is a deficient number, since it is larger than the sum of its proper divisors (9833669).

20423691 is an equidigital number, since it uses as much as digits as its factorization.

20423691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 756442 (or 756436 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 20423691 is about 4519.2577930452. The cubic root of 20423691 is about 273.3451738211.

The spelling of 20423691 in words is "twenty million, four hundred twenty-three thousand, six hundred ninety-one".