1020040405 has 4 divisors (see below), whose sum is σ = 1224048492. Its totient is φ = 816032320.

The previous prime is 1020040339. The next prime is 1020040433. The reversal of 1020040405 is 5040400201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5040400201 = 1409 ⋅3577289.

It can be written as a sum of positive squares in 2 ways, for example, as 166874724 + 853165681 = 12918^2 + 29209^2 .

It is not a de Polignac number, because 1020040405 - 2¹⁷ = 1019909333 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102004036 + ... + 102004045.

It is an arithmetic number, because the mean of its divisors is an integer number (306012123).

Almost surely, 2^1020040405 is an apocalyptic number.

It is an amenable number.

1020040405 is a deficient number, since it is larger than the sum of its proper divisors (204008087).

1020040405 is an equidigital number, since it uses as much as digits as its factorization.

1020040405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204008086.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 1020040405 is about 31938.0714038904. The cubic root of 1020040405 is about 1006.6360010809.

Adding to 1020040405 its reverse (5040400201), we get a palindrome (6060440606).

It can be divided in two parts, 10200 and 40405, that added together give a palindrome (50605).

The spelling of 1020040405 in words is "one billion, twenty million, forty thousand, four hundred five".