21154437047 has 2 divisors, whose sum is σ = 21154437048. Its totient is φ = 21154437046.

The previous prime is 21154437041. The next prime is 21154437061. The reversal of 21154437047 is 74073445112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21154437047 - 2⁸ = 21154436791 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21154437047.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21154437041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577218523 + 10577218524.

It is an arithmetic number, because the mean of its divisors is an integer number (10577218524).

Almost surely, 2^21154437047 is an apocalyptic number.

21154437047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21154437047 is an equidigital number, since it uses as much as digits as its factorization.

21154437047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 94080, while the sum is 38.

The spelling of 21154437047 in words is "twenty-one billion, one hundred fifty-four million, four hundred thirty-seven thousand, forty-seven".