1021010021 has 8 divisors (see below), whose sum is σ = 1082047320. Its totient is φ = 960081408.

The previous prime is 1021009993. The next prime is 1021010041. The reversal of 1021010021 is 1200101201.

It can be written as a sum of positive squares in 4 ways, for example, as 153412996 + 867597025 = 12386^2 + 29455^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1021010021 is a prime.

It is a super-2 number, since 2×1021010021² = 2084922925964840882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021009990 and 1021010008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021010041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7406 + ... + 45791.

It is an arithmetic number, because the mean of its divisors is an integer number (135255915).

Almost surely, 2^1021010021 is an apocalyptic number.

It is an amenable number.

1021010021 is a deficient number, since it is larger than the sum of its proper divisors (61037299).

1021010021 is a wasteful number, since it uses less digits than its factorization.

1021010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54343.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 1021010021 is about 31953.2474249488. The cubic root of 1021010021 is about 1006.9548581459.

Adding to 1021010021 its reverse (1200101201), we get a palindrome (2221111222).

The spelling of 1021010021 in words is "one billion, twenty-one million, ten thousand, twenty-one".