1020002581 has 4 divisors (see below), whose sum is σ = 1098464332. Its totient is φ = 941540832.

The previous prime is 1020002563. The next prime is 1020002623. The reversal of 1020002581 is 1852000201.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 451180081 + 568822500 = 21241^2 + 23850^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020002581 - 2¹³ = 1019994389 is a prime.

It is a super-2 number, since 2×1020002581² = 2080810530493323122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020002381) 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, 39230856 + ... + 39230881.

It is an arithmetic number, because the mean of its divisors is an integer number (274616083).

Almost surely, 2^1020002581 is an apocalyptic number.

It is an amenable number.

1020002581 is a deficient number, since it is larger than the sum of its proper divisors (78461751).

1020002581 is an equidigital number, since it uses as much as digits as its factorization.

1020002581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78461750.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 1020002581 is about 31937.4792524394. The cubic root of 1020002581 is about 1006.6235586095.

Adding to 1020002581 its reverse (1852000201), we get a palindrome (2872002782).

The spelling of 1020002581 in words is "one billion, twenty million, two thousand, five hundred eighty-one".