1428639840 has 72 divisors (see below), whose sum is σ = 4875238368. Its totient is φ = 380970240.

The previous prime is 1428639787. The next prime is 1428639851. The reversal of 1428639840 is 489368241.

It is a happy number.

1428639840 is a `hidden beast` number, since 1 + 4 + 2 + 8 + 639 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 494616 + ... + 497495.

It is an arithmetic number, because the mean of its divisors is an integer number (67711644).

Almost surely, 2^1428639840 is an apocalyptic number.

1428639840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1428639840 is an abundant number, since it is smaller than the sum of its proper divisors (3446598528).

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

1428639840 is a wasteful number, since it uses less digits than its factorization.

1428639840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 992132 (or 992121 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The square root of 1428639840 is about 37797.3522882225. The cubic root of 1428639840 is about 1126.2658580761.

The spelling of 1428639840 in words is "one billion, four hundred twenty-eight million, six hundred thirty-nine thousand, eight hundred forty".