155520221520 has 40 divisors (see below), whose sum is σ = 482112687456. Its totient is φ = 41472059008.

The previous prime is 155520221497. The next prime is 155520221573. The reversal of 155520221520 is 25122025551.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×155520221520² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 324000222 + ... + 324000701.

Almost surely, 2^155520221520 is an apocalyptic number.

155520221520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

155520221520 is an abundant number, since it is smaller than the sum of its proper divisors (326592465936).

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

155520221520 is a wasteful number, since it uses less digits than its factorization.

155520221520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 648000939 (or 648000933 counting only the distinct ones).

The product of its (nonzero) digits is 10000, while the sum is 30.

The spelling of 155520221520 in words is "one hundred fifty-five billion, five hundred twenty million, two hundred twenty-one thousand, five hundred twenty".