1020725621 has 4 divisors (see below), whose sum is σ = 1022023392. Its totient is φ = 1019427852.

The previous prime is 1020725599. The next prime is 1020725647. The reversal of 1020725621 is 1265270201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1265270201 = 13 ⋅97328477.

It is a cyclic number.

It is not a de Polignac number, because 1020725621 - 2¹⁴ = 1020709237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020725821) 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, 647705 + ... + 649278.

It is an arithmetic number, because the mean of its divisors is an integer number (255505848).

Almost surely, 2^1020725621 is an apocalyptic number.

It is an amenable number.

1020725621 is a deficient number, since it is larger than the sum of its proper divisors (1297771).

1020725621 is an equidigital number, since it uses as much as digits as its factorization.

1020725621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1297770.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 1020725621 is about 31948.7968631058. The cubic root of 1020725621 is about 1006.8613544747.

Adding to 1020725621 its reverse (1265270201), we get a palindrome (2285995822).

The spelling of 1020725621 in words is "one billion, twenty million, seven hundred twenty-five thousand, six hundred twenty-one".