1721520679 has 16 divisors (see below), whose sum is σ = 1782144000. Its totient is φ = 1662294816.

The previous prime is 1721520643. The next prime is 1721520727. The reversal of 1721520679 is 9760251271.

It is a cyclic number.

It is not a de Polignac number, because 1721520679 - 2²¹ = 1719423527 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 (1721520379) 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, 674097 + ... + 676645.

It is an arithmetic number, because the mean of its divisors is an integer number (111384000).

Almost surely, 2^1721520679 is an apocalyptic number.

1721520679 is a deficient number, since it is larger than the sum of its proper divisors (60623321).

1721520679 is a wasteful number, since it uses less digits than its factorization.

1721520679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2814.

The product of its (nonzero) digits is 52920, while the sum is 40.

The square root of 1721520679 is about 41491.2120695455. The cubic root of 1721520679 is about 1198.4982786540.

The spelling of 1721520679 in words is "one billion, seven hundred twenty-one million, five hundred twenty thousand, six hundred seventy-nine".