155421005 has 24 divisors (see below), whose sum is σ = 201681792. Its totient is φ = 114758336.

The previous prime is 155421001. The next prime is 155421103. The reversal of 155421005 is 500124551.

It is a happy number.

It is not a de Polignac number, because 155421005 - 2² = 155421001 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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (155421001) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 95912 + ... + 97518.

It is an arithmetic number, because the mean of its divisors is an integer number (8403408).

Almost surely, 2^155421005 is an apocalyptic number.

It is an amenable number.

155421005 is a deficient number, since it is larger than the sum of its proper divisors (46260787).

155421005 is a wasteful number, since it uses less digits than its factorization.

155421005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1693 (or 1664 counting only the distinct ones).

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

The square root of 155421005 is about 12466.7961000411. The cubic root of 155421005 is about 537.6544412877.

Adding to 155421005 its reverse (500124551), we get a palindrome (655545556).

The spelling of 155421005 in words is "one hundred fifty-five million, four hundred twenty-one thousand, five".