28931407 has 2 divisors, whose sum is σ = 28931408. Its totient is φ = 28931406.

The previous prime is 28931381. The next prime is 28931411. The reversal of 28931407 is 70413982.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28931407 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28931477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14465703 + 14465704.

It is an arithmetic number, because the mean of its divisors is an integer number (14465704).

Almost surely, 2^28931407 is an apocalyptic number.

28931407 is a deficient number, since it is larger than the sum of its proper divisors (1).

28931407 is an equidigital number, since it uses as much as digits as its factorization.

28931407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 28931407 is about 5378.7923365752. The cubic root of 28931407 is about 306.9892621100.

The spelling of 28931407 in words is "twenty-eight million, nine hundred thirty-one thousand, four hundred seven".