120728021 has 4 divisors (see below), whose sum is σ = 120830412. Its totient is φ = 120625632.

The previous prime is 120728017. The next prime is 120728029. The reversal of 120728021 is 120827021.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 88078225 + 32649796 = 9385^2 + 5714^2 .

It is a cyclic number.

It is not a de Polignac number, because 120728021 - 2² = 120728017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (120728029) 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, 49406 + ... + 51791.

It is an arithmetic number, because the mean of its divisors is an integer number (30207603).

Almost surely, 2^120728021 is an apocalyptic number.

It is an amenable number.

120728021 is a deficient number, since it is larger than the sum of its proper divisors (102391).

120728021 is a wasteful number, since it uses less digits than its factorization.

120728021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102390.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 120728021 is about 10987.6303632767. The cubic root of 120728021 is about 494.2378790089.

The spelling of 120728021 in words is "one hundred twenty million, seven hundred twenty-eight thousand, twenty-one".