1721440861 has 16 divisors (see below), whose sum is σ = 1996503040. Its totient is φ = 1453800960.

The previous prime is 1721440837. The next prime is 1721440867. The reversal of 1721440861 is 1680441271.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1721440861 - 2⁷ = 1721440733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721440867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 149956 + ... + 161026.

It is an arithmetic number, because the mean of its divisors is an integer number (124781440).

Almost surely, 2^1721440861 is an apocalyptic number.

It is an amenable number.

1721440861 is a deficient number, since it is larger than the sum of its proper divisors (275062179).

1721440861 is a wasteful number, since it uses less digits than its factorization.

1721440861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11404.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 1721440861 is about 41490.2501920632. The cubic root of 1721440861 is about 1198.4797556479.

The spelling of 1721440861 in words is "one billion, seven hundred twenty-one million, four hundred forty thousand, eight hundred sixty-one".