691948553 has 4 divisors (see below), whose sum is σ = 693449988. Its totient is φ = 690447120.

The previous prime is 691948511. The next prime is 691948589. The reversal of 691948553 is 355849196.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 418939024 + 273009529 = 20468^2 + 16523^2 .

It is a cyclic number.

It is not a de Polignac number, because 691948553 - 2¹⁴ = 691932169 is a prime.

It is a super-3 number, since 3×691948553³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691948253) 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, 750026 + ... + 750947.

It is an arithmetic number, because the mean of its divisors is an integer number (173362497).

Almost surely, 2^691948553 is an apocalyptic number.

It is an amenable number.

691948553 is a deficient number, since it is larger than the sum of its proper divisors (1501435).

691948553 is a wasteful number, since it uses less digits than its factorization.

691948553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1501434.

The product of its digits is 1166400, while the sum is 50.

The square root of 691948553 is about 26304.9149970115. The cubic root of 691948553 is about 884.4866219334.

The spelling of 691948553 in words is "six hundred ninety-one million, nine hundred forty-eight thousand, five hundred fifty-three".