1020400434 has 72 divisors (see below), whose sum is σ = 2345166252. Its totient is φ = 320604480.

The previous prime is 1020400417. The next prime is 1020400463. The reversal of 1020400434 is 4340040201.

It can be written as a sum of positive squares in 2 ways, for example, as 909203409 + 111197025 = 30153^2 + 10545^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2423544 + ... + 2423964.

Almost surely, 2^1020400434 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1020400434, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1172583126).

1020400434 is an abundant number, since it is smaller than the sum of its proper divisors (1324765818).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1020400434 is a wasteful number, since it uses less digits than its factorization.

1020400434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840 (or 818 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 1020400434 is about 31943.7072676294. The cubic root of 1020400434 is about 1006.7544197632.

Adding to 1020400434 its reverse (4340040201), we get a palindrome (5360440635).

The spelling of 1020400434 in words is "one billion, twenty million, four hundred thousand, four hundred thirty-four".