21969021961 has 8 divisors (see below), whose sum is σ = 22347125000. Its totient is φ = 21591498240.

The previous prime is 21969021901. The next prime is 21969021983. The reversal of 21969021961 is 16912096912.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 424360000 + 21544661961 = 20600^2 + 146781^2 .

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 21969021961 - 2²¹ = 21966924809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21969021901) 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, 67986 + ... + 220363.

It is an arithmetic number, because the mean of its divisors is an integer number (2793390625).

Almost surely, 2^21969021961 is an apocalyptic number.

It is an amenable number.

21969021961 is a deficient number, since it is larger than the sum of its proper divisors (378103039).

21969021961 is a wasteful number, since it uses less digits than its factorization.

21969021961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289659.

The product of its (nonzero) digits is 104976, while the sum is 46.

The spelling of 21969021961 in words is "twenty-one billion, nine hundred sixty-nine million, twenty-one thousand, nine hundred sixty-one".