1661984402 has 8 divisors (see below), whose sum is σ = 2684744076. Its totient is φ = 767069712.

The previous prime is 1661984381. The next prime is 1661984449. The reversal of 1661984402 is 2044891661.

It can be written as a sum of positive squares in 2 ways, for example, as 1534994041 + 126990361 = 39179^2 + 11269^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1661984402.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 31961213 + ... + 31961264.

Almost surely, 2^1661984402 is an apocalyptic number.

1661984402 is a deficient number, since it is larger than the sum of its proper divisors (1022759674).

1661984402 is a wasteful number, since it uses less digits than its factorization.

1661984402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63922492.

The product of its (nonzero) digits is 82944, while the sum is 41.

The square root of 1661984402 is about 40767.4429171122. The cubic root of 1661984402 is about 1184.5197724158.

The spelling of 1661984402 in words is "one billion, six hundred sixty-one million, nine hundred eighty-four thousand, four hundred two".