1020399636 has 96 divisors (see below), whose sum is σ = 2718817920. Its totient is φ = 295833600.

The previous prime is 1020399613. The next prime is 1020399659. The reversal of 1020399636 is 6369930201.

It is an interprime number because it is at equal distance from previous prime (1020399613) and next prime (1020399659).

It is a junction number, because it is equal to n+sod(n) for n = 1020399594 and 1020399603.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 155706 + ... + 162126.

It is an arithmetic number, because the mean of its divisors is an integer number (28321020).

Almost surely, 2^1020399636 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1020399636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1359408960).

1020399636 is an abundant number, since it is smaller than the sum of its proper divisors (1698418284).

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

1020399636 is a wasteful number, since it uses less digits than its factorization.

1020399636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6505 (or 6503 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 39.

The square root of 1020399636 is about 31943.6947769039. The cubic root of 1020399636 is about 1006.7541573204.

The spelling of 1020399636 in words is "one billion, twenty million, three hundred ninety-nine thousand, six hundred thirty-six".