1020631621 has 4 divisors (see below), whose sum is σ = 1024264044. Its totient is φ = 1016999200.

The previous prime is 1020631613. The next prime is 1020631627. The reversal of 1020631621 is 1261360201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1261360201 = 19 ⋅66387379.

It can be written as a sum of positive squares in 2 ways, for example, as 268500996 + 752130625 = 16386^2 + 27425^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020631621 - 2³ = 1020631613 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1020631592 and 1020631601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020631627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1815790 + ... + 1816351.

It is an arithmetic number, because the mean of its divisors is an integer number (256066011).

Almost surely, 2^1020631621 is an apocalyptic number.

It is an amenable number.

1020631621 is a deficient number, since it is larger than the sum of its proper divisors (3632423).

1020631621 is an equidigital number, since it uses as much as digits as its factorization.

1020631621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3632422.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 1020631621 is about 31947.3257253248. The cubic root of 1020631621 is about 1006.8304457856.

Adding to 1020631621 its reverse (1261360201), we get a palindrome (2281991822).

It can be divided in two parts, 102063 and 1621, that added together give a square (103684 = 322²).

The spelling of 1020631621 in words is "one billion, twenty million, six hundred thirty-one thousand, six hundred twenty-one".