661355001 has 12 divisors (see below), whose sum is σ = 975616512. Its totient is φ = 431522136.

The previous prime is 661354997. The next prime is 661355003. The reversal of 661355001 is 100553166.

It is a happy number.

It is not a de Polignac number, because 661355001 - 2² = 661354997 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661355003) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 781321 + ... + 782166.

It is an arithmetic number, because the mean of its divisors is an integer number (81301376).

Almost surely, 2^661355001 is an apocalyptic number.

It is an amenable number.

661355001 is a deficient number, since it is larger than the sum of its proper divisors (314261511).

661355001 is a wasteful number, since it uses less digits than its factorization.

661355001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1563540 (or 1563537 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 27.

The square root of 661355001 is about 25716.8233069328. The cubic root of 661355001 is about 871.2541918810.

The spelling of 661355001 in words is "six hundred sixty-one million, three hundred fifty-five thousand, one".