321561407 has 2 divisors, whose sum is σ = 321561408. Its totient is φ = 321561406.

The previous prime is 321561379. The next prime is 321561433. The reversal of 321561407 is 704165123.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 321561407 - 2¹⁸ = 321299263 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 321561407.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321561437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160780703 + 160780704.

It is an arithmetic number, because the mean of its divisors is an integer number (160780704).

Almost surely, 2^321561407 is an apocalyptic number.

321561407 is a deficient number, since it is larger than the sum of its proper divisors (1).

321561407 is an equidigital number, since it uses as much as digits as its factorization.

321561407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 321561407 is about 17932.1333644383. The cubic root of 321561407 is about 685.1010609769.

The spelling of 321561407 in words is "three hundred twenty-one million, five hundred sixty-one thousand, four hundred seven".