155221487 has 2 divisors, whose sum is σ = 155221488. Its totient is φ = 155221486.

The previous prime is 155221481. The next prime is 155221511. The reversal of 155221487 is 784122551.

It is a weak prime.

It is an emirp because it is prime and its reverse (784122551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155221487 - 2¹⁰ = 155220463 is a prime.

It is a Chen prime.

It is equal to p_8721296 and since 155221487 and 8721296 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155221481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77610743 + 77610744.

It is an arithmetic number, because the mean of its divisors is an integer number (77610744).

Almost surely, 2^155221487 is an apocalyptic number.

155221487 is a deficient number, since it is larger than the sum of its proper divisors (1).

155221487 is an equidigital number, since it uses as much as digits as its factorization.

155221487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22400, while the sum is 35.

The square root of 155221487 is about 12458.7915545610. The cubic root of 155221487 is about 537.4242757574.

The spelling of 155221487 in words is "one hundred fifty-five million, two hundred twenty-one thousand, four hundred eighty-seven".