1020400989 has 32 divisors (see below), whose sum is σ = 1448979840. Its totient is φ = 637593600.

The previous prime is 1020400987. The next prime is 1020401017. The reversal of 1020400989 is 9890040201.

It is not a de Polignac number, because 1020400989 - 2¹ = 1020400987 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020400987) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 859054 + ... + 860240.

It is an arithmetic number, because the mean of its divisors is an integer number (45280620).

Almost surely, 2^1020400989 is an apocalyptic number.

It is an amenable number.

1020400989 is a deficient number, since it is larger than the sum of its proper divisors (428578851).

1020400989 is a wasteful number, since it uses less digits than its factorization.

1020400989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1501.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 1020400989 is about 31943.7159547852. The cubic root of 1020400989 is about 1006.7546022891.

The spelling of 1020400989 in words is "one billion, twenty million, four hundred thousand, nine hundred eighty-nine".