690398561 has 4 divisors (see below), whose sum is σ = 696850992. Its totient is φ = 683946132.

The previous prime is 690398531. The next prime is 690398591. The reversal of 690398561 is 165893096.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (690398531) and next prime (690398591).

It is a cyclic number.

It is not a de Polignac number, because 690398561 - 2¹⁴ = 690382177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (690398531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3226055 + ... + 3226268.

It is an arithmetic number, because the mean of its divisors is an integer number (174212748).

Almost surely, 2^690398561 is an apocalyptic number.

It is an amenable number.

690398561 is a deficient number, since it is larger than the sum of its proper divisors (6452431).

690398561 is a wasteful number, since it uses less digits than its factorization.

690398561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6452430.

The product of its (nonzero) digits is 349920, while the sum is 47.

The square root of 690398561 is about 26275.4364568888. The cubic root of 690398561 is about 883.8256999055.

The spelling of 690398561 in words is "six hundred ninety million, three hundred ninety-eight thousand, five hundred sixty-one".