120721556 has 12 divisors (see below), whose sum is σ = 223690068. Its totient is φ = 56810112.

The previous prime is 120721547. The next prime is 120721561. The reversal of 120721556 is 655127021.

It can be written as a sum of positive squares in 2 ways, for example, as 104448400 + 16273156 = 10220^2 + 4034^2 .

It is a super-2 number, since 2×120721556² = 29147388166122272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 887591 + ... + 887726.

It is an arithmetic number, because the mean of its divisors is an integer number (18640839).

Almost surely, 2^120721556 is an apocalyptic number.

It is an amenable number.

120721556 is a deficient number, since it is larger than the sum of its proper divisors (102968512).

120721556 is a wasteful number, since it uses less digits than its factorization.

120721556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1775338 (or 1775336 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 29.

The square root of 120721556 is about 10987.3361648764. The cubic root of 120721556 is about 494.2290566855.

Adding to 120721556 its reverse (655127021), we get a palindrome (775848577).

The spelling of 120721556 in words is "one hundred twenty million, seven hundred twenty-one thousand, five hundred fifty-six".