1020001001 has 2 divisors, whose sum is σ = 1020001002. Its totient is φ = 1020001000.

The previous prime is 1020000899. The next prime is 1020001013. The reversal of 1020001001 is 1001000201.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 925619776 + 94381225 = 30424^2 + 9715^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020001001 - 2²² = 1015806697 is a prime.

It is a super-3 number, since 3×1020001001³ (a number of 28 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1020001051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510000500 + 510000501.

It is an arithmetic number, because the mean of its divisors is an integer number (510000501).

Almost surely, 2^1020001001 is an apocalyptic number.

It is an amenable number.

1020001001 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020001001 is an equidigital number, since it uses as much as digits as its factorization.

1020001001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 1020001001 is about 31937.4545166017. The cubic root of 1020001001 is about 1006.6230388506.

Adding to 1020001001 its reverse (1001000201), we get a palindrome (2021001202).

The spelling of 1020001001 in words is "one billion, twenty million, one thousand, one".