661650769 has 4 divisors (see below), whose sum is σ = 712546996. Its totient is φ = 610754544.

The previous prime is 661650751. The next prime is 661650793. The reversal of 661650769 is 967056166.

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 354945600 + 306705169 = 18840^2 + 17513^2 .

It is a cyclic number.

It is not a de Polignac number, because 661650769 - 2⁹ = 661650257 is a prime.

It is a super-2 number, since 2×661650769² = 875563480236582722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661650709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25448094 + ... + 25448119.

It is an arithmetic number, because the mean of its divisors is an integer number (178136749).

Almost surely, 2^661650769 is an apocalyptic number.

It is an amenable number.

661650769 is a deficient number, since it is larger than the sum of its proper divisors (50896227).

661650769 is a wasteful number, since it uses less digits than its factorization.

661650769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50896226.

The product of its (nonzero) digits is 408240, while the sum is 46.

The square root of 661650769 is about 25722.5731411148. The cubic root of 661650769 is about 871.3840518931.

The spelling of 661650769 in words is "six hundred sixty-one million, six hundred fifty thousand, seven hundred sixty-nine".