30402728 has 8 divisors (see below), whose sum is σ = 57005130. Its totient is φ = 15201360.

The previous prime is 30402721. The next prime is 30402739. The reversal of 30402728 is 82720403.

It can be written as a sum of positive squares in only one way, i.e., 30228004 + 174724 = 5498^2 + 418^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 30402697 and 30402706.

It is not an unprimeable number, because it can be changed into a prime (30402721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1900163 + ... + 1900178.

Almost surely, 2^30402728 is an apocalyptic number.

It is an amenable number.

30402728 is a deficient number, since it is larger than the sum of its proper divisors (26602402).

30402728 is a wasteful number, since it uses less digits than its factorization.

30402728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3800347 (or 3800343 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 30402728 is about 5513.8668826877. The cubic root of 30402728 is about 312.1074854298.

The spelling of 30402728 in words is "thirty million, four hundred two thousand, seven hundred twenty-eight".