1661050551 has 4 divisors (see below), whose sum is σ = 2214734072. Its totient is φ = 1107367032.

The previous prime is 1661050543. The next prime is 1661050591. The reversal of 1661050551 is 1550501661.

1661050551 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 1661050551 - 2³ = 1661050543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661050591) 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, 276841756 + ... + 276841761.

It is an arithmetic number, because the mean of its divisors is an integer number (553683518).

Almost surely, 2^1661050551 is an apocalyptic number.

1661050551 is a deficient number, since it is larger than the sum of its proper divisors (553683521).

1661050551 is an equidigital number, since it uses as much as digits as its factorization.

1661050551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553683520.

The product of its (nonzero) digits is 4500, while the sum is 30.

The square root of 1661050551 is about 40755.9879158879. The cubic root of 1661050551 is about 1184.2978745813.

It can be divided in two parts, 16610 and 50551, that added together give a triangular number (67161 = T₃₆₆).

The spelling of 1661050551 in words is "one billion, six hundred sixty-one million, fifty thousand, five hundred fifty-one".