661101047 has 4 divisors (see below), whose sum is σ = 661919040. Its totient is φ = 660283056.

The previous prime is 661101037. The next prime is 661101053. The reversal of 661101047 is 740101166.

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 661101047 - 2¹⁴ = 661084663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661101037) 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, 407783 + ... + 409400.

It is an arithmetic number, because the mean of its divisors is an integer number (165479760).

Almost surely, 2^661101047 is an apocalyptic number.

661101047 is a deficient number, since it is larger than the sum of its proper divisors (817993).

661101047 is an equidigital number, since it uses as much as digits as its factorization.

661101047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817992.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 661101047 is about 25711.8853256621. The cubic root of 661101047 is about 871.1426598430.

The spelling of 661101047 in words is "six hundred sixty-one million, one hundred one thousand, forty-seven".