661425407 has 24 divisors (see below), whose sum is σ = 709059120. Its totient is φ = 616429440.

The previous prime is 661425403. The next prime is 661425463. The reversal of 661425407 is 704524166.

It is not a de Polignac number, because 661425407 - 2² = 661425403 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 (661425403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6068069 + ... + 6068177.

It is an arithmetic number, because the mean of its divisors is an integer number (29544130).

Almost surely, 2^661425407 is an apocalyptic number.

661425407 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

661425407 is a deficient number, since it is larger than the sum of its proper divisors (47633713).

661425407 is a wasteful number, since it uses less digits than its factorization.

661425407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 661425407 is about 25718.1921409729. The cubic root of 661425407 is about 871.2851078772.

The spelling of 661425407 in words is "six hundred sixty-one million, four hundred twenty-five thousand, four hundred seven".