1020401021 has 4 divisors (see below), whose sum is σ = 1027249500. Its totient is φ = 1013552544.

The previous prime is 1020401017. The next prime is 1020401077. The reversal of 1020401021 is 1201040201.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 324180025 + 696220996 = 18005^2 + 26386^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020401021 - 2² = 1020401017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1020400993 and 1020401011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020401321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3424016 + ... + 3424313.

It is an arithmetic number, because the mean of its divisors is an integer number (256812375).

Almost surely, 2^1020401021 is an apocalyptic number.

It is an amenable number.

1020401021 is a deficient number, since it is larger than the sum of its proper divisors (6848479).

1020401021 is an equidigital number, since it uses as much as digits as its factorization.

1020401021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6848478.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 1020401021 is about 31943.7164556662. The cubic root of 1020401021 is about 1006.7546128131.

Adding to 1020401021 its reverse (1201040201), we get a palindrome (2221441222).

The spelling of 1020401021 in words is "one billion, twenty million, four hundred one thousand, twenty-one".