1021210001001 has 24 divisors (see below), whose sum is σ = 1481848158024. Its totient is φ = 677689555200.

The previous prime is 1021210000981. The next prime is 1021210001011. The reversal of 1021210001001 is 1001000121201.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8892301401 + 1012317699600 = 94299^2 + 1006140^2 .

It is not a de Polignac number, because 1021210001001 - 2²⁶ = 1021142892137 is a prime.

It is a super-2 number, since 2×1021210001001² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (1021210001011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1744645 + ... + 2255261.

It is an arithmetic number, because the mean of its divisors is an integer number (61743673251).

Almost surely, 2^{1021210001001} is an apocalyptic number.

It is an amenable number.

1021210001001 is a deficient number, since it is larger than the sum of its proper divisors (460638157023).

1021210001001 is a wasteful number, since it uses less digits than its factorization.

1021210001001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511641 (or 511638 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 1021210001001 its reverse (1001000121201), we get a palindrome (2022210122202).

The spelling of 1021210001001 in words is "one trillion, twenty-one billion, two hundred ten million, one thousand, one".