1661028481 has 4 divisors (see below), whose sum is σ = 1898318272. Its totient is φ = 1423738692.

The previous prime is 1661028461. The next prime is 1661028541. The reversal of 1661028481 is 1848201661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1661028481 - 2¹³ = 1661020289 is a prime.

It is a super-2 number, since 2×1661028481² = 5518031229386334722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1661028481.

It is not an unprimeable number, because it can be changed into a prime (1661028451) 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, 118644885 + ... + 118644898.

It is an arithmetic number, because the mean of its divisors is an integer number (474579568).

Almost surely, 2^1661028481 is an apocalyptic number.

It is an amenable number.

1661028481 is a deficient number, since it is larger than the sum of its proper divisors (237289791).

1661028481 is an equidigital number, since it uses as much as digits as its factorization.

1661028481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237289790.

The product of its (nonzero) digits is 18432, while the sum is 37.

The square root of 1661028481 is about 40755.7171572284. The cubic root of 1661028481 is about 1184.2926293928.

The spelling of 1661028481 in words is "one billion, six hundred sixty-one million, twenty-eight thousand, four hundred eighty-one".