1020642640 has 40 divisors (see below), whose sum is σ = 2379166920. Its totient is φ = 407195136.

The previous prime is 1020642629. The next prime is 1020642697. The reversal of 1020642640 is 462460201.

1020642640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 271854144 + 748788496 = 16488^2 + 27364^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×1020642640² = 2083422797172339200, which contains 22 as substring.

It is a congruent number.

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, 14722 + ... + 47518.

It is an arithmetic number, because the mean of its divisors is an integer number (59479173).

Almost surely, 2^1020642640 is an apocalyptic number.

1020642640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1020642640 is an abundant number, since it is smaller than the sum of its proper divisors (1358524280).

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

1020642640 is a wasteful number, since it uses less digits than its factorization.

1020642640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33199 (or 33193 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 1020642640 is about 31947.4981806088. The cubic root of 1020642640 is about 1006.8340691055.

The spelling of 1020642640 in words is "one billion, twenty million, six hundred forty-two thousand, six hundred forty".