155580421 has 4 divisors (see below), whose sum is σ = 155613952. Its totient is φ = 155546892.

The previous prime is 155580409. The next prime is 155580433. The reversal of 155580421 is 124085551.

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: 124085551 = 1951 ⋅63601.

It is an interprime number because it is at equal distance from previous prime (155580409) and next prime (155580433).

It is a cyclic number.

It is not a de Polignac number, because 155580421 - 2²¹ = 153483269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155580401) 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, 8421 + ... + 19546.

It is an arithmetic number, because the mean of its divisors is an integer number (38903488).

Almost surely, 2^155580421 is an apocalyptic number.

It is an amenable number.

155580421 is a deficient number, since it is larger than the sum of its proper divisors (33531).

155580421 is an equidigital number, since it uses as much as digits as its factorization.

155580421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33530.

The product of its (nonzero) digits is 8000, while the sum is 31.

The square root of 155580421 is about 12473.1880848482. The cubic root of 155580421 is about 537.8382033055.

The spelling of 155580421 in words is "one hundred fifty-five million, five hundred eighty thousand, four hundred twenty-one".