28921577 has 2 divisors, whose sum is σ = 28921578. Its totient is φ = 28921576.

The previous prime is 28921507. The next prime is 28921589. The reversal of 28921577 is 77512982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23921881 + 4999696 = 4891^2 + 2236^2 .

It is a cyclic number.

It is not a de Polignac number, because 28921577 - 2¹² = 28917481 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28921507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14460788 + 14460789.

It is an arithmetic number, because the mean of its divisors is an integer number (14460789).

Almost surely, 2^28921577 is an apocalyptic number.

It is an amenable number.

28921577 is a deficient number, since it is larger than the sum of its proper divisors (1).

28921577 is an equidigital number, since it uses as much as digits as its factorization.

28921577 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 70560, while the sum is 41.

The square root of 28921577 is about 5377.8784850534. The cubic root of 28921577 is about 306.9544896764.

The spelling of 28921577 in words is "twenty-eight million, nine hundred twenty-one thousand, five hundred seventy-seven".