155452921 has 4 divisors (see below), whose sum is σ = 167410852. Its totient is φ = 143494992.

The previous prime is 155452901. The next prime is 155452933. The reversal of 155452921 is 129254551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129254551 = 5099 ⋅25349.

It can be written as a sum of positive squares in 2 ways, for example, as 19404025 + 136048896 = 4405^2 + 11664^2 .

It is a cyclic number.

It is not a de Polignac number, because 155452921 - 2²⁵ = 121898489 is a prime.

It is a super-2 number, since 2×155452921² = 48331221294864482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155452901) 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, 5978946 + ... + 5978971.

It is an arithmetic number, because the mean of its divisors is an integer number (41852713).

Almost surely, 2^155452921 is an apocalyptic number.

It is an amenable number.

155452921 is a deficient number, since it is larger than the sum of its proper divisors (11957931).

155452921 is a wasteful number, since it uses less digits than its factorization.

155452921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11957930.

The product of its digits is 18000, while the sum is 34.

The square root of 155452921 is about 12468.0760745193. The cubic root of 155452921 is about 537.6912415573.

The spelling of 155452921 in words is "one hundred fifty-five million, four hundred fifty-two thousand, nine hundred twenty-one".