1023520021 has 2 divisors, whose sum is σ = 1023520022. Its totient is φ = 1023520020.

The previous prime is 1023520009. The next prime is 1023520049. The reversal of 1023520021 is 1200253201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 876988996 + 146531025 = 29614^2 + 12105^2 .

It is a cyclic number.

It is not a de Polignac number, because 1023520021 - 2⁵ = 1023519989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1023519977 and 1023520004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1023520621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 511760010 + 511760011.

It is an arithmetic number, because the mean of its divisors is an integer number (511760011).

Almost surely, 2^1023520021 is an apocalyptic number.

It is an amenable number.

1023520021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1023520021 is an equidigital number, since it uses as much as digits as its factorization.

1023520021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 1023520021 is about 31992.4994490896. The cubic root of 1023520021 is about 1007.7793320628.

Adding to 1023520021 its reverse (1200253201), we get a palindrome (2223773222).

The spelling of 1023520021 in words is "one billion, twenty-three million, five hundred twenty thousand, twenty-one".