1656615961 has 36 divisors (see below), whose sum is σ = 2281244196. Its totient is φ = 1191516480.

The previous prime is 1656615953. The next prime is 1656615967. The reversal of 1656615961 is 1695166561.

It can be written as a sum of positive squares in 2 ways, for example, as 192099600 + 1464516361 = 13860^2 + 38269^2 .

It is not a de Polignac number, because 1656615961 - 2³ = 1656615953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1656615967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 66331 + ... + 87823.

Almost surely, 2^1656615961 is an apocalyptic number.

1656615961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1656615961 is a deficient number, since it is larger than the sum of its proper divisors (624628235).

1656615961 is a wasteful number, since it uses less digits than its factorization.

1656615961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21542 (or 21524 counting only the distinct ones).

The product of its digits is 291600, while the sum is 46.

The square root of 1656615961 is about 40701.5474030165. The cubic root of 1656615961 is about 1183.2430087948.

The spelling of 1656615961 in words is "one billion, six hundred fifty-six million, six hundred fifteen thousand, nine hundred sixty-one".