1955220661 has 8 divisors (see below), whose sum is σ = 1966802264. Its totient is φ = 1943654400.

The previous prime is 1955220653. The next prime is 1955220667. The reversal of 1955220661 is 1660225591.

It can be written as a sum of positive squares in 4 ways, for example, as 375158161 + 1580062500 = 19369^2 + 39750^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1955220661 - 2³ = 1955220653 is a prime.

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 1955220661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1955220667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 340111 + ... + 345811.

It is an arithmetic number, because the mean of its divisors is an integer number (245850283).

Almost surely, 2^1955220661 is an apocalyptic number.

It is an amenable number.

1955220661 is a deficient number, since it is larger than the sum of its proper divisors (11581603).

1955220661 is a wasteful number, since it uses less digits than its factorization.

1955220661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7671.

The product of its (nonzero) digits is 32400, while the sum is 37.

The square root of 1955220661 is about 44217.8771652371. The cubic root of 1955220661 is about 1250.4469145415.

The spelling of 1955220661 in words is "one billion, nine hundred fifty-five million, two hundred twenty thousand, six hundred sixty-one".