19720811 has 8 divisors (see below), whose sum is σ = 21546048. Its totient is φ = 17901000.

The previous prime is 19720787. The next prime is 19720829. The reversal of 19720811 is 11802791.

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 19720811 - 2¹⁰ = 19719787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19720891) 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, 12116 + ... + 13646.

It is an arithmetic number, because the mean of its divisors is an integer number (2693256).

Almost surely, 2^19720811 is an apocalyptic number.

19720811 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19720811 is a deficient number, since it is larger than the sum of its proper divisors (1825237).

19720811 is a wasteful number, since it uses less digits than its factorization.

19720811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2713.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 19720811 is about 4440.8119753036. The cubic root of 19720811 is about 270.1727792144.

The spelling of 19720811 in words is "nineteen million, seven hundred twenty thousand, eight hundred eleven".