28721097 has 24 divisors (see below), whose sum is σ = 43250688. Its totient is φ = 18345600.

The previous prime is 28721093. The next prime is 28721113. The reversal of 28721097 is 79012782.

It is not a de Polignac number, because 28721097 - 2² = 28721093 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28721093) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31072 + ... + 31982.

It is an arithmetic number, because the mean of its divisors is an integer number (1802112).

Almost surely, 2^28721097 is an apocalyptic number.

It is an amenable number.

28721097 is a deficient number, since it is larger than the sum of its proper divisors (14529591).

28721097 is a wasteful number, since it uses less digits than its factorization.

28721097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061 (or 1058 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 28721097 is about 5359.2067510034. The cubic root of 28721097 is about 306.2435904809.

It can be divided in two parts, 2872 and 1097, that added together give a square (3969 = 63²).

The spelling of 28721097 in words is "twenty-eight million, seven hundred twenty-one thousand, ninety-seven".