145555921 has 12 divisors (see below), whose sum is σ = 179281188. Its totient is φ = 117422592.

The previous prime is 145555913. The next prime is 145555931. The reversal of 145555921 is 129555541.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 129072321 + 16483600 = 11361^2 + 4060^2 .

It is not a de Polignac number, because 145555921 - 2³ = 145555913 is a prime.

It is a super-2 number, since 2×145555921² = 42373052276316482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (145555931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 86536 + ... + 88201.

It is an arithmetic number, because the mean of its divisors is an integer number (14940099).

Almost surely, 2^145555921 is an apocalyptic number.

It is an amenable number.

145555921 is a deficient number, since it is larger than the sum of its proper divisors (33725267).

145555921 is a wasteful number, since it uses less digits than its factorization.

145555921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174768 (or 174761 counting only the distinct ones).

The product of its digits is 45000, while the sum is 37.

The square root of 145555921 is about 12064.6558591615. The cubic root of 145555921 is about 526.0293287005.

The spelling of 145555921 in words is "one hundred forty-five million, five hundred fifty-five thousand, nine hundred twenty-one".