1020155421 has 4 divisors (see below), whose sum is σ = 1360207232. Its totient is φ = 680103612.

The previous prime is 1020155419. The next prime is 1020155447. The reversal of 1020155421 is 1245510201.

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.

It is not a de Polignac number, because 1020155421 - 2¹ = 1020155419 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 (1020155401) 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, 170025901 + ... + 170025906.

It is an arithmetic number, because the mean of its divisors is an integer number (340051808).

Almost surely, 2^1020155421 is an apocalyptic number.

It is an amenable number.

1020155421 is a deficient number, since it is larger than the sum of its proper divisors (340051811).

1020155421 is an equidigital number, since it uses as much as digits as its factorization.

1020155421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340051810.

The product of its (nonzero) digits is 400, while the sum is 21.

The square root of 1020155421 is about 31939.8719627991. The cubic root of 1020155421 is about 1006.6738345152.

Adding to 1020155421 its reverse (1245510201), we get a palindrome (2265665622).

The spelling of 1020155421 in words is "one billion, twenty million, one hundred fifty-five thousand, four hundred twenty-one".