691361387 has 2 divisors, whose sum is σ = 691361388. Its totient is φ = 691361386.

The previous prime is 691361369. The next prime is 691361471. The reversal of 691361387 is 783163196.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691361387 - 2²⁴ = 674584171 is a prime.

It is not a weakly prime, because it can be changed into another prime (691361887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345680693 + 345680694.

It is an arithmetic number, because the mean of its divisors is an integer number (345680694).

Almost surely, 2^691361387 is an apocalyptic number.

691361387 is a deficient number, since it is larger than the sum of its proper divisors (1).

691361387 is an equidigital number, since it uses as much as digits as its factorization.

691361387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 44.

The square root of 691361387 is about 26293.7518623722. The cubic root of 691361387 is about 884.2363685306.

The spelling of 691361387 in words is "six hundred ninety-one million, three hundred sixty-one thousand, three hundred eighty-seven".