1428205981 has 4 divisors (see below), whose sum is σ = 1442929852. Its totient is φ = 1413482112.

The previous prime is 1428205951. The next prime is 1428206009. The reversal of 1428205981 is 1895028241.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 886014756 + 542191225 = 29766^2 + 23285^2 .

It is a cyclic number.

It is not a de Polignac number, because 1428205981 - 2²⁵ = 1394651549 is a prime.

It is a super-2 number, since 2×1428205981² = 4079544648328344722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1428205951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7361790 + ... + 7361983.

It is an arithmetic number, because the mean of its divisors is an integer number (360732463).

Almost surely, 2^1428205981 is an apocalyptic number.

It is an amenable number.

1428205981 is a deficient number, since it is larger than the sum of its proper divisors (14723871).

1428205981 is an equidigital number, since it uses as much as digits as its factorization.

1428205981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14723870.

The product of its (nonzero) digits is 46080, while the sum is 40.

The square root of 1428205981 is about 37791.6125747500. The cubic root of 1428205981 is about 1126.1518358577.

The spelling of 1428205981 in words is "one billion, four hundred twenty-eight million, two hundred five thousand, nine hundred eighty-one".