20400442 has 16 divisors (see below), whose sum is σ = 33014952. Its totient is φ = 9418240.

The previous prime is 20400439. The next prime is 20400463. The reversal of 20400442 is 24400402.

It can be written as a sum of positive squares in 4 ways, for example, as 17547721 + 2852721 = 4189^2 + 1689^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3859 + ... + 7462.

Almost surely, 2^20400442 is an apocalyptic number.

20400442 is a deficient number, since it is larger than the sum of its proper divisors (12614510).

20400442 is a wasteful number, since it uses less digits than its factorization.

20400442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11393.

The product of its (nonzero) digits is 256, while the sum is 16.

The square root of 20400442 is about 4516.6848462119. The cubic root of 20400442 is about 273.2414149912.

Adding to 20400442 its reverse (24400402), we get a palindrome (44800844).

The spelling of 20400442 in words is "twenty million, four hundred thousand, four hundred forty-two".