661090895 has 4 divisors (see below), whose sum is σ = 793309080. Its totient is φ = 528872712.

The previous prime is 661090879. The next prime is 661090949. The reversal of 661090895 is 598090166.

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

It is a cyclic number.

It is not a de Polignac number, because 661090895 - 2⁴ = 661090879 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66109085 + ... + 66109094.

It is an arithmetic number, because the mean of its divisors is an integer number (198327270).

Almost surely, 2^661090895 is an apocalyptic number.

661090895 is a deficient number, since it is larger than the sum of its proper divisors (132218185).

661090895 is a wasteful number, since it uses less digits than its factorization.

661090895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132218184.

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 661090895 is about 25711.6879064755. The cubic root of 661090895 is about 871.1382006731.

The spelling of 661090895 in words is "six hundred sixty-one million, ninety thousand, eight hundred ninety-five".