20409631 has 4 divisors (see below), whose sum is σ = 22265064. Its totient is φ = 18554200.

The previous prime is 20409601. The next prime is 20409643. The reversal of 20409631 is 13690402.

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 20409631 - 2¹³ = 20401439 is a prime.

It is a super-2 number, since 2×20409631² = 833106075112322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20409596 and 20409605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20409601) 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, 927700 + ... + 927721.

It is an arithmetic number, because the mean of its divisors is an integer number (5566266).

Almost surely, 2^20409631 is an apocalyptic number.

20409631 is a deficient number, since it is larger than the sum of its proper divisors (1855433).

20409631 is a wasteful number, since it uses less digits than its factorization.

20409631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1855432.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 20409631 is about 4517.7019600678. The cubic root of 20409631 is about 273.2824343389.

The spelling of 20409631 in words is "twenty million, four hundred nine thousand, six hundred thirty-one".