820618988 has 24 divisors (see below), whose sum is σ = 1663724832. Its totient is φ = 346875264.

The previous prime is 820618979. The next prime is 820618993. The reversal of 820618988 is 889816028.

It is a super-2 number, since 2×820618988² = 1346831046932288288, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 198695 + ... + 202782.

It is an arithmetic number, because the mean of its divisors is an integer number (69321868).

Almost surely, 2^820618988 is an apocalyptic number.

It is an amenable number.

820618988 is an abundant number, since it is smaller than the sum of its proper divisors (843105844).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

820618988 is a wasteful number, since it uses less digits than its factorization.

820618988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401561 (or 401559 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 50.

The square root of 820618988 is about 28646.4480869793. The cubic root of 820618988 is about 936.2256179884.

The spelling of 820618988 in words is "eight hundred twenty million, six hundred eighteen thousand, nine hundred eighty-eight".