1021388155 has 16 divisors (see below), whose sum is σ = 1272996864. Its totient is φ = 785881440.

The previous prime is 1021388153. The next prime is 1021388189. The reversal of 1021388155 is 5518831201.

It is not a de Polignac number, because 1021388155 - 2¹ = 1021388153 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 1021388155.

It is not an unprimeable number, because it can be changed into a prime (1021388153) 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 15 ways as a sum of consecutive naturals, for example, 5052 + ... + 45478.

It is an arithmetic number, because the mean of its divisors is an integer number (79562304).

Almost surely, 2^1021388155 is an apocalyptic number.

1021388155 is a deficient number, since it is larger than the sum of its proper divisors (251608709).

1021388155 is a wasteful number, since it uses less digits than its factorization.

1021388155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40626.

The product of its (nonzero) digits is 9600, while the sum is 34.

The square root of 1021388155 is about 31959.1638657835. The cubic root of 1021388155 is about 1007.0791523462.

The spelling of 1021388155 in words is "one billion, twenty-one million, three hundred eighty-eight thousand, one hundred fifty-five".