21819053961 has 6 divisors (see below), whose sum is σ = 31516411290. Its totient is φ = 14546035968.

The previous prime is 21819053947. The next prime is 21819053969. The reversal of 21819053961 is 16935091812.

21819053961 is a `hidden beast` number, since 21 + 8 + 1 + 90 + 539 + 6 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20604879936 + 1214174025 = 143544^2 + 34845^2 .

It is not a de Polignac number, because 21819053961 - 2⁶ = 21819053897 is a prime.

It is a super-2 number, since 2×21819053961² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21819053969) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1212169656 + ... + 1212169673.

It is an arithmetic number, because the mean of its divisors is an integer number (5252735215).

Almost surely, 2^21819053961 is an apocalyptic number.

It is an amenable number.

21819053961 is a deficient number, since it is larger than the sum of its proper divisors (9697357329).

21819053961 is a wasteful number, since it uses less digits than its factorization.

21819053961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2424339335 (or 2424339332 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The spelling of 21819053961 in words is "twenty-one billion, eight hundred nineteen million, fifty-three thousand, nine hundred sixty-one".