20971801 has 4 divisors (see below), whose sum is σ = 22075600. Its totient is φ = 19868004.

The previous prime is 20971799. The next prime is 20971807. The reversal of 20971801 is 10817902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10817902 = 2 ⋅5408951.

It is a cyclic number.

It is not a de Polignac number, because 20971801 - 2¹ = 20971799 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 20971801.

It is not an unprimeable number, because it can be changed into a prime (20971807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 551871 + ... + 551908.

It is an arithmetic number, because the mean of its divisors is an integer number (5518900).

Almost surely, 2^20971801 is an apocalyptic number.

It is an amenable number.

20971801 is a deficient number, since it is larger than the sum of its proper divisors (1103799).

20971801 is a wasteful number, since it uses less digits than its factorization.

20971801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1103798.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 20971801 is about 4579.4978982417. The cubic root of 20971801 is about 275.7688720002.

It can be divided in two parts, 209 and 71801, that added together give a triangular number (72010 = T₃₇₉).

The spelling of 20971801 in words is "twenty million, nine hundred seventy-one thousand, eight hundred one".