28215311 has 2 divisors, whose sum is σ = 28215312. Its totient is φ = 28215310.

The previous prime is 28215283. The next prime is 28215331. The reversal of 28215311 is 11351282.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28215311 is a prime.

It is a super-2 number, since 2×28215311² = 1592207549653442, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28215331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14107655 + 14107656.

It is an arithmetic number, because the mean of its divisors is an integer number (14107656).

Almost surely, 2^28215311 is an apocalyptic number.

28215311 is a deficient number, since it is larger than the sum of its proper divisors (1).

28215311 is an equidigital number, since it uses as much as digits as its factorization.

28215311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 23.

The square root of 28215311 is about 5311.8086373664. The cubic root of 28215311 is about 304.4352570274.

Adding to 28215311 its reverse (11351282), we get a palindrome (39566593).

The spelling of 28215311 in words is "twenty-eight million, two hundred fifteen thousand, three hundred eleven".