21309726841 has 8 divisors (see below), whose sum is σ = 23001218240. Its totient is φ = 19625704272.

The previous prime is 21309726839. The next prime is 21309726853. The reversal of 21309726841 is 14862790312.

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 21309726841 - 2¹ = 21309726839 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21309726871) 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, 1861275 + ... + 1872688.

It is an arithmetic number, because the mean of its divisors is an integer number (2875152280).

Almost surely, 2^21309726841 is an apocalyptic number.

It is an amenable number.

21309726841 is a deficient number, since it is larger than the sum of its proper divisors (1691491399).

21309726841 is a wasteful number, since it uses less digits than its factorization.

21309726841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3734415.

The product of its (nonzero) digits is 145152, while the sum is 43.

The spelling of 21309726841 in words is "twenty-one billion, three hundred nine million, seven hundred twenty-six thousand, eight hundred forty-one".