21275471947 has 8 divisors (see below), whose sum is σ = 21680900640. Its totient is φ = 20870191680.

The previous prime is 21275471897. The next prime is 21275471963. The reversal of 21275471947 is 74917457212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21275471947 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 21275471947.

It is not an unprimeable number, because it can be changed into a prime (21275471447) 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, 277447 + ... + 345727.

It is an arithmetic number, because the mean of its divisors is an integer number (2710112580).

Almost surely, 2^21275471947 is an apocalyptic number.

21275471947 is a deficient number, since it is larger than the sum of its proper divisors (405428693).

21275471947 is an equidigital number, since it uses as much as digits as its factorization.

21275471947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74213.

The product of its digits is 987840, while the sum is 49.

The spelling of 21275471947 in words is "twenty-one billion, two hundred seventy-five million, four hundred seventy-one thousand, nine hundred forty-seven".