1661632243 has 2 divisors, whose sum is σ = 1661632244. Its totient is φ = 1661632242.

The previous prime is 1661632199. The next prime is 1661632249. The reversal of 1661632243 is 3422361661.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661632243 is a prime.

It is a super-2 number, since 2×1661632243² = 5522043421954422098, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1661632199 and 1661632208.

It is not a weakly prime, because it can be changed into another prime (1661632249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830816121 + 830816122.

It is an arithmetic number, because the mean of its divisors is an integer number (830816122).

Almost surely, 2^1661632243 is an apocalyptic number.

1661632243 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661632243 is an equidigital number, since it uses as much as digits as its factorization.

1661632243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 34.

The square root of 1661632243 is about 40763.1235677542. The cubic root of 1661632243 is about 1184.4361036072.

The spelling of 1661632243 in words is "one billion, six hundred sixty-one million, six hundred thirty-two thousand, two hundred forty-three".