1020131221 has 4 divisors (see below), whose sum is σ = 1023454432. Its totient is φ = 1016808012.

The previous prime is 1020131051. The next prime is 1020131251. The reversal of 1020131221 is 1221310201.

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: 1221310201 = 137 ⋅8914673.

It is a cyclic number.

It is not a de Polignac number, because 1020131221 - 2¹⁹ = 1019606933 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 (1020131251) 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, 1661145 + ... + 1661758.

It is an arithmetic number, because the mean of its divisors is an integer number (255863608).

Almost surely, 2^1020131221 is an apocalyptic number.

It is an amenable number.

1020131221 is a deficient number, since it is larger than the sum of its proper divisors (3323211).

1020131221 is an equidigital number, since it uses as much as digits as its factorization.

1020131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3323210.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1020131221 is about 31939.4931237175. The cubic root of 1020131221 is about 1006.6658743884.

Adding to 1020131221 its reverse (1221310201), we get a palindrome (2241441422).

The spelling of 1020131221 in words is "one billion, twenty million, one hundred thirty-one thousand, two hundred twenty-one".