2171661644 has 24 divisors (see below), whose sum is σ = 3878089488. Its totient is φ = 1063699520.

The previous prime is 2171661629. The next prime is 2171661659. The reversal of 2171661644 is 4461661712.

It is an interprime number because it is at equal distance from previous prime (2171661629) and next prime (2171661659).

It is a super-2 number, since 2×2171661644² = 9432228592041565472, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2171661598 and 2171661607.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 135959 + ... + 151089.

It is an arithmetic number, because the mean of its divisors is an integer number (161587062).

Almost surely, 2^2171661644 is an apocalyptic number.

It is an amenable number.

2171661644 is a deficient number, since it is larger than the sum of its proper divisors (1706427844).

2171661644 is a wasteful number, since it uses less digits than its factorization.

2171661644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15865 (or 15863 counting only the distinct ones).

The product of its digits is 48384, while the sum is 38.

The square root of 2171661644 is about 46601.0905880968. The cubic root of 2171661644 is about 1294.9829594812.

The spelling of 2171661644 in words is "two billion, one hundred seventy-one million, six hundred sixty-one thousand, six hundred forty-four".