661498647 has 4 divisors (see below), whose sum is σ = 881998200. Its totient is φ = 440999096.

The previous prime is 661498631. The next prime is 661498687. The reversal of 661498647 is 746894166.

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 661498647 - 2⁴ = 661498631 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661498647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661498687) 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, 110249772 + ... + 110249777.

It is an arithmetic number, because the mean of its divisors is an integer number (220499550).

Almost surely, 2^661498647 is an apocalyptic number.

661498647 is a deficient number, since it is larger than the sum of its proper divisors (220499553).

661498647 is a wasteful number, since it uses less digits than its factorization.

661498647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220499552.

The product of its digits is 1741824, while the sum is 51.

The square root of 661498647 is about 25719.6159963558. The cubic root of 661498647 is about 871.3172659837.

The spelling of 661498647 in words is "six hundred sixty-one million, four hundred ninety-eight thousand, six hundred forty-seven".