155212220 has 12 divisors (see below), whose sum is σ = 325945704. Its totient is φ = 62084880.

The previous prime is 155212217. The next prime is 155212229. The reversal of 155212220 is 22212551.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 7760611 = 155212220 / (1 + 5 + 5 + 2 + 1 + 2 + 2 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 155212192 and 155212201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155212229) 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, 3880286 + ... + 3880325.

It is an arithmetic number, because the mean of its divisors is an integer number (27162142).

Almost surely, 2^155212220 is an apocalyptic number.

155212220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

155212220 is an abundant number, since it is smaller than the sum of its proper divisors (170733484).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

155212220 is a wasteful number, since it uses less digits than its factorization.

155212220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7760620 (or 7760618 counting only the distinct ones).

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

The square root of 155212220 is about 12458.4196429563. The cubic root of 155212220 is about 537.4135804815.

Adding to 155212220 its reverse (22212551), we get a palindrome (177424771).

The spelling of 155212220 in words is "one hundred fifty-five million, two hundred twelve thousand, two hundred twenty".