1656561993 has 8 divisors (see below), whose sum is σ = 2209515648. Its totient is φ = 1103991504.

The previous prime is 1656561943. The next prime is 1656562001. The reversal of 1656561993 is 3991656561.

It is a happy number.

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

It is not a de Polignac number, because 1656561993 - 2²⁹ = 1119691081 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1656561943) 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, 85546 + ... + 103107.

It is an arithmetic number, because the mean of its divisors is an integer number (276189456).

Almost surely, 2^1656561993 is an apocalyptic number.

It is an amenable number.

1656561993 is a deficient number, since it is larger than the sum of its proper divisors (552953655).

1656561993 is a wasteful number, since it uses less digits than its factorization.

1656561993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191583.

The product of its digits is 1312200, while the sum is 51.

The square root of 1656561993 is about 40700.8844252800. The cubic root of 1656561993 is about 1183.2301597190.

The spelling of 1656561993 in words is "one billion, six hundred fifty-six million, five hundred sixty-one thousand, nine hundred ninety-three".