661913493 has 8 divisors (see below), whose sum is σ = 884957568. Its totient is φ = 440072544.

The previous prime is 661913467. The next prime is 661913503. The reversal of 661913493 is 394319166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661913493 - 2¹² = 661909397 is a prime.

It is a super-2 number, since 2×661913493² = 876258944430922098, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661913443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 299496 + ... + 301697.

It is an arithmetic number, because the mean of its divisors is an integer number (110619696).

Almost surely, 2^661913493 is an apocalyptic number.

It is an amenable number.

661913493 is a deficient number, since it is larger than the sum of its proper divisors (223044075).

661913493 is a wasteful number, since it uses less digits than its factorization.

661913493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 601563.

The product of its digits is 104976, while the sum is 42.

The square root of 661913493 is about 25727.6795105971. The cubic root of 661913493 is about 871.4993711420.

The spelling of 661913493 in words is "six hundred sixty-one million, nine hundred thirteen thousand, four hundred ninety-three".