155454040221 has 4 divisors (see below), whose sum is σ = 207272053632. Its totient is φ = 103636026812.

The previous prime is 155454040207. The next prime is 155454040241. The reversal of 155454040221 is 122040454551.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 122040454551 = 3 ⋅40680151517.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155454040221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155454040241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25909006701 + ... + 25909006706.

It is an arithmetic number, because the mean of its divisors is an integer number (51818013408).

Almost surely, 2^155454040221 is an apocalyptic number.

It is an amenable number.

155454040221 is a deficient number, since it is larger than the sum of its proper divisors (51818013411).

155454040221 is an equidigital number, since it uses as much as digits as its factorization.

155454040221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51818013410.

The product of its (nonzero) digits is 32000, while the sum is 33.

Adding to 155454040221 its reverse (122040454551), we get a palindrome (277494494772).

The spelling of 155454040221 in words is "one hundred fifty-five billion, four hundred fifty-four million, forty thousand, two hundred twenty-one".