21377015447 has 2 divisors, whose sum is σ = 21377015448. Its totient is φ = 21377015446.

The previous prime is 21377015353. The next prime is 21377015453. The reversal of 21377015447 is 74451077312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21377015447 - 2¹⁸ = 21376753303 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21377015047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10688507723 + 10688507724.

It is an arithmetic number, because the mean of its divisors is an integer number (10688507724).

Almost surely, 2^21377015447 is an apocalyptic number.

21377015447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21377015447 is an equidigital number, since it uses as much as digits as its factorization.

21377015447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 164640, while the sum is 41.

The spelling of 21377015447 in words is "twenty-one billion, three hundred seventy-seven million, fifteen thousand, four hundred forty-seven".