155221004 has 12 divisors (see below), whose sum is σ = 271744704. Its totient is φ = 77579664.

The previous prime is 155220991. The next prime is 155221007. The reversal of 155221004 is 400122551.

It is not an unprimeable number, because it can be changed into a prime (155221007) 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, 6542 + ... + 18794.

It is an arithmetic number, because the mean of its divisors is an integer number (22645392).

Almost surely, 2^155221004 is an apocalyptic number.

It is an amenable number.

155221004 is a deficient number, since it is larger than the sum of its proper divisors (116523700).

155221004 is a wasteful number, since it uses less digits than its factorization.

155221004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15424 (or 15422 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 155221004 is about 12458.7721706435. The cubic root of 155221004 is about 537.4237183256.

Adding to 155221004 its reverse (400122551), we get a palindrome (555343555).

The spelling of 155221004 in words is "one hundred fifty-five million, two hundred twenty-one thousand, four".