28138631 has 2 divisors, whose sum is σ = 28138632. Its totient is φ = 28138630.

The previous prime is 28138603. The next prime is 28138651. The reversal of 28138631 is 13683182.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28138631 - 2¹⁸ = 27876487 is a prime.

It is a super-2 number, since 2×28138631² = 1583565109108322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28138651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14069315 + 14069316.

It is an arithmetic number, because the mean of its divisors is an integer number (14069316).

Almost surely, 2^28138631 is an apocalyptic number.

28138631 is a deficient number, since it is larger than the sum of its proper divisors (1).

28138631 is an equidigital number, since it uses as much as digits as its factorization.

28138631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 32.

The square root of 28138631 is about 5304.5858462278. The cubic root of 28138631 is about 304.1592216188.

The spelling of 28138631 in words is "twenty-eight million, one hundred thirty-eight thousand, six hundred thirty-one".