491020001 has 2 divisors, whose sum is σ = 491020002. Its totient is φ = 491020000.

The previous prime is 491019953. The next prime is 491020009. The reversal of 491020001 is 100020194.

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., 408646225 + 82373776 = 20215^2 + 9076^2 .

It is a cyclic number.

It is not a de Polignac number, because 491020001 - 2⁶ = 491019937 is a prime.

It is a super-2 number, since 2×491020001² = 482201282764080002, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (491020009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245510000 + 245510001.

It is an arithmetic number, because the mean of its divisors is an integer number (245510001).

Almost surely, 2^491020001 is an apocalyptic number.

It is an amenable number.

491020001 is a deficient number, since it is larger than the sum of its proper divisors (1).

491020001 is an equidigital number, since it uses as much as digits as its factorization.

491020001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 491020001 is about 22158.9711178114. The cubic root of 491020001 is about 788.9201723941.

Adding to 491020001 its reverse (100020194), we get a palindrome (591040195).

The spelling of 491020001 in words is "four hundred ninety-one million, twenty thousand, one".