1660651261 has 4 divisors (see below), whose sum is σ = 1663601472. Its totient is φ = 1657701052.

The previous prime is 1660651253. The next prime is 1660651283. The reversal of 1660651261 is 1621560661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1660651261 - 2³ = 1660651253 is a prime.

It is a super-2 number, since 2×1660651261² = 5515525221321780242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660651211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1474261 + ... + 1475386.

It is an arithmetic number, because the mean of its divisors is an integer number (415900368).

Almost surely, 2^1660651261 is an apocalyptic number.

It is an amenable number.

1660651261 is a deficient number, since it is larger than the sum of its proper divisors (2950211).

1660651261 is an equidigital number, since it uses as much as digits as its factorization.

1660651261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2950210.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 1660651261 is about 40751.0890774713. The cubic root of 1660651261 is about 1184.2029715506.

The spelling of 1660651261 in words is "one billion, six hundred sixty million, six hundred fifty-one thousand, two hundred sixty-one".