1013021621 has 4 divisors (see below), whose sum is σ = 1014103692. Its totient is φ = 1011939552.

The previous prime is 1013021599. The next prime is 1013021623. The reversal of 1013021621 is 1261203101.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1261203101 = 31 ⋅40683971.

It can be written as a sum of positive squares in 2 ways, for example, as 110019121 + 903002500 = 10489^2 + 30050^2 .

It is a cyclic number.

It is not a de Polignac number, because 1013021621 - 2¹⁰ = 1013020597 is a prime.

It is a super-2 number, since 2×1013021621² = 2052425609226935282, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1013021621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1013021623) 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, 539630 + ... + 541503.

It is an arithmetic number, because the mean of its divisors is an integer number (253525923).

Almost surely, 2^1013021621 is an apocalyptic number.

It is an amenable number.

1013021621 is a deficient number, since it is larger than the sum of its proper divisors (1082071).

1013021621 is an equidigital number, since it uses as much as digits as its factorization.

1013021621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1082070.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1013021621 is about 31828.0005812492. Note that the first 3 decimals coincide. The cubic root of 1013021621 is about 1004.3218351660.

Adding to 1013021621 its reverse (1261203101), we get a palindrome (2274224722).

The spelling of 1013021621 in words is "one billion, thirteen million, twenty-one thousand, six hundred twenty-one".