19979539801 has 27 divisors (see below), whose sum is σ = 22066888287.
Its totient is φ = 18081364080.
The previous prime is 19979539759. The next prime is 19979539837. The reversal of 19979539801 is 10893597991.
The square root of 19979539801 is 141349.
It is a perfect power (a square), and thus also a powerful number.
It can be written as a sum of positive squares in only one way, i.e., 2955553225 + 17023986576 = 54365^2 + 130476^2
It is not a de Polignac number, because 19979539801 - 27 = 19979539673 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 19979539801.
It is not an unprimeable number, because it can be changed into a prime (19979539001) by changing a digit.
It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 152515506 + ... + 152515636.
Almost surely, 219979539801 is an apocalyptic number.
19979539801 is the 141349-th square number.
19979539801 is the 70675-th centered octagonal number.
It is an amenable number.
19979539801 is a deficient number, since it is larger than the sum of its proper divisors (2087348486).
19979539801 is an frugal number, since it uses more digits than its factorization.
19979539801 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 454 (or 227 counting only the distinct ones).
The product of its (nonzero) digits is 5511240, while the sum is 61.
The spelling of 19979539801 in words is "nineteen billion, nine hundred seventy-nine million, five hundred thirty-nine thousand, eight hundred one".