19181973001 has 9 divisors (see below), whose sum is σ = 20379199399. Its totient is φ = 18051405664.

The previous prime is 19181972993. The next prime is 19181973017. The reversal of 19181973001 is 10037918191.

The square root of 19181973001 is 138499.

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., 14934062025 + 4247910976 = 122205^2 + 65176^2 .

It is not a de Polignac number, because 19181973001 - 2³ = 19181972993 is a prime.

It is a super-2 number, since 2×19181973001² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19181973101) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2350410 + ... + 2358556.

Almost surely, 2^19181973001 is an apocalyptic number.

19181973001 is the 138499-th square number.

19181973001 is the 69250-th centered octagonal number.

It is an amenable number.

19181973001 is a deficient number, since it is larger than the sum of its proper divisors (1197226398).

19181973001 is an frugal number, since it uses more digits than its factorization.

19181973001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16328 (or 8164 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 40.

The spelling of 19181973001 in words is "nineteen billion, one hundred eighty-one million, nine hundred seventy-three thousand, one".