1661472777 has 16 divisors (see below), whose sum is σ = 2223809280. Its totient is φ = 1103402832.

The previous prime is 1661472751. The next prime is 1661472793. The reversal of 1661472777 is 7772741661.

It is not a de Polignac number, because 1661472777 - 2⁷ = 1661472649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661472277) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1270558 + ... + 1271864.

It is an arithmetic number, because the mean of its divisors is an integer number (138988080).

Almost surely, 2^1661472777 is an apocalyptic number.

It is an amenable number.

1661472777 is a deficient number, since it is larger than the sum of its proper divisors (562336503).

1661472777 is a wasteful number, since it uses less digits than its factorization.

1661472777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2612.

The product of its digits is 691488, while the sum is 48.

The square root of 1661472777 is about 40761.1675127198. The cubic root of 1661472777 is about 1184.3982124852.

The spelling of 1661472777 in words is "one billion, six hundred sixty-one million, four hundred seventy-two thousand, seven hundred seventy-seven".