1021010100021 has 12 divisors (see below), whose sum is σ = 1475210319180. Its totient is φ = 680480498880.

The previous prime is 1021010099927. The next prime is 1021010100059. The reversal of 1021010100021 is 1200010101201.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 255803292900 + 765206807121 = 505770^2 + 874761^2 .

It is not a de Polignac number, because 1021010100021 - 2¹¹ = 1021010097973 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 1021010099976 and 1021010100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021010101021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16041570 + ... + 16105091.

It is an arithmetic number, because the mean of its divisors is an integer number (122934193265).

Almost surely, 2^{1021010100021} is an apocalyptic number.

It is an amenable number.

1021010100021 is a deficient number, since it is larger than the sum of its proper divisors (454200219159).

1021010100021 is a wasteful number, since it uses less digits than its factorization.

1021010100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32150196 (or 32150193 counting only the distinct ones).

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

Adding to 1021010100021 its reverse (1200010101201), we get a palindrome (2221020201222).

The spelling of 1021010100021 in words is "one trillion, twenty-one billion, ten million, one hundred thousand, twenty-one".