2145731661 has 16 divisors (see below), whose sum is σ = 3203133120. Its totient is φ = 1419565680.

The previous prime is 2145731641. The next prime is 2145731677. The reversal of 2145731661 is 1661375412.

2145731661 is a `hidden beast` number, since 2 + 14 + 573 + 16 + 61 = 666.

It is not a de Polignac number, because 2145731661 - 2⁹ = 2145731149 is a prime.

It is a super-2 number, since 2×2145731661² = 9208328722035637842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2145731641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 299790 + ... + 306863.

It is an arithmetic number, because the mean of its divisors is an integer number (200195820).

Almost surely, 2^2145731661 is an apocalyptic number.

It is an amenable number.

2145731661 is a deficient number, since it is larger than the sum of its proper divisors (1057401459).

2145731661 is a wasteful number, since it uses less digits than its factorization.

2145731661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606793 (or 606787 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The square root of 2145731661 is about 46322.0429277466. The cubic root of 2145731661 is about 1289.8082083715.

The spelling of 2145731661 in words is "two billion, one hundred forty-five million, seven hundred thirty-one thousand, six hundred sixty-one".