28213531 has 2 divisors, whose sum is σ = 28213532. Its totient is φ = 28213530.

The previous prime is 28213519. The next prime is 28213541. The reversal of 28213531 is 13531282.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28213531 - 2⁷ = 28213403 is a prime.

It is a super-2 number, since 2×28213531² = 1592006662975922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28213496 and 28213505.

It is not a weakly prime, because it can be changed into another prime (28213511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14106765 + 14106766.

It is an arithmetic number, because the mean of its divisors is an integer number (14106766).

Almost surely, 2^28213531 is an apocalyptic number.

28213531 is a deficient number, since it is larger than the sum of its proper divisors (1).

28213531 is an equidigital number, since it uses as much as digits as its factorization.

28213531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 25.

The square root of 28213531 is about 5311.6410835071. The cubic root of 28213531 is about 304.4288549933.

The spelling of 28213531 in words is "twenty-eight million, two hundred thirteen thousand, five hundred thirty-one".