661949403 has 4 divisors (see below), whose sum is σ = 882599208. Its totient is φ = 441299600.

The previous prime is 661949359. The next prime is 661949413. The reversal of 661949403 is 304949166.

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 661949403 - 2¹⁷ = 661818331 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661949413) 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, 110324898 + ... + 110324903.

It is an arithmetic number, because the mean of its divisors is an integer number (220649802).

Almost surely, 2^661949403 is an apocalyptic number.

661949403 is a deficient number, since it is larger than the sum of its proper divisors (220649805).

661949403 is a wasteful number, since it uses less digits than its factorization.

661949403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220649804.

The product of its (nonzero) digits is 139968, while the sum is 42.

The square root of 661949403 is about 25728.3773876240. The cubic root of 661949403 is about 871.5151309942.

The spelling of 661949403 in words is "six hundred sixty-one million, nine hundred forty-nine thousand, four hundred three".