155522021 has 16 divisors (see below), whose sum is σ = 166053888. Its totient is φ = 145345200.

The previous prime is 155521991. The next prime is 155522027. The reversal of 155522021 is 120225551.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155522021 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155522027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 213560 + ... + 214286.

It is an arithmetic number, because the mean of its divisors is an integer number (10378368).

Almost surely, 2^155522021 is an apocalyptic number.

It is an amenable number.

155522021 is a deficient number, since it is larger than the sum of its proper divisors (10531867).

155522021 is a wasteful number, since it uses less digits than its factorization.

155522021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 952.

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 155522021 is about 12470.8468437392. The cubic root of 155522021 is about 537.7708990312.

Adding to 155522021 its reverse (120225551), we get a palindrome (275747572).

The spelling of 155522021 in words is "one hundred fifty-five million, five hundred twenty-two thousand, twenty-one".