1988785406 has 4 divisors (see below), whose sum is σ = 2983178112. Its totient is φ = 994392702.

The previous prime is 1988785387. The next prime is 1988785417. The reversal of 1988785406 is 6045878891.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×1988785406² = 7910534782237169672, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 497196350 + ... + 497196353.

It is an arithmetic number, because the mean of its divisors is an integer number (745794528).

Almost surely, 2^1988785406 is an apocalyptic number.

1988785406 is a deficient number, since it is larger than the sum of its proper divisors (994392706).

1988785406 is an equidigital number, since it uses as much as digits as its factorization.

1988785406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 994392705.

The product of its (nonzero) digits is 3870720, while the sum is 56.

The square root of 1988785406 is about 44595.8003179672. The cubic root of 1988785406 is about 1257.5617173840.

The spelling of 1988785406 in words is "one billion, nine hundred eighty-eight million, seven hundred eighty-five thousand, four hundred six".