991020004 has 24 divisors (see below), whose sum is σ = 1907434368. Its totient is φ = 447660960.

The previous prime is 991019923. The next prime is 991020007. The reversal of 991020004 is 400020199.

991020004 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (991020007) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 200302 + ... + 205189.

It is an arithmetic number, because the mean of its divisors is an integer number (79476432).

Almost surely, 2^991020004 is an apocalyptic number.

991020004 is a gapful number since it is divisible by the number (94) formed by its first and last digit.

It is an amenable number.

991020004 is a deficient number, since it is larger than the sum of its proper divisors (916414364).

991020004 is a wasteful number, since it uses less digits than its factorization.

991020004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405555 (or 405553 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 991020004 is about 31480.4701997921. The cubic root of 991020004 is about 996.9976629935.

The spelling of 991020004 in words is "nine hundred ninety-one million, twenty thousand, four".