661407903 has 16 divisors (see below), whose sum is σ = 1055238240. Its totient is φ = 407020032.

The previous prime is 661407889. The next prime is 661407907. The reversal of 661407903 is 309704166.

It is not a de Polignac number, because 661407903 - 2⁶ = 661407839 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661407907) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 941826 + ... + 942527.

It is an arithmetic number, because the mean of its divisors is an integer number (65952390).

Almost surely, 2^661407903 is an apocalyptic number.

661407903 is a deficient number, since it is larger than the sum of its proper divisors (393830337).

661407903 is a wasteful number, since it uses less digits than its factorization.

661407903 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1884375 (or 1884369 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 661407903 is about 25717.8518348637. The cubic root of 661407903 is about 871.2774218963.

The spelling of 661407903 in words is "six hundred sixty-one million, four hundred seven thousand, nine hundred three".