1020231521 has 4 divisors (see below), whose sum is σ = 1021651200. Its totient is φ = 1018811844.

The previous prime is 1020231479. The next prime is 1020231529. The reversal of 1020231521 is 1251320201.

It is a happy number.

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: 1251320201 = 83 ⋅15076147.

It is a cyclic number.

It is not a de Polignac number, because 1020231521 - 2¹⁴ = 1020215137 is a prime.

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 1020231521.

It is not an unprimeable number, because it can be changed into a prime (1020231529) 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, 708761 + ... + 710198.

It is an arithmetic number, because the mean of its divisors is an integer number (255412800).

Almost surely, 2^1020231521 is an apocalyptic number.

It is an amenable number.

1020231521 is a deficient number, since it is larger than the sum of its proper divisors (1419679).

1020231521 is an equidigital number, since it uses as much as digits as its factorization.

1020231521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1419678.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 1020231521 is about 31941.0632415391. The cubic root of 1020231521 is about 1006.6988653332.

Adding to 1020231521 its reverse (1251320201), we get a palindrome (2271551722).

The spelling of 1020231521 in words is "one billion, twenty million, two hundred thirty-one thousand, five hundred twenty-one".