21977147 has 2 divisors, whose sum is σ = 21977148. Its totient is φ = 21977146.

The previous prime is 21977143. The next prime is 21977159. The reversal of 21977147 is 74177912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21977147 - 2² = 21977143 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21977147.

It is not a weakly prime, because it can be changed into another prime (21977143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10988573 + 10988574.

It is an arithmetic number, because the mean of its divisors is an integer number (10988574).

Almost surely, 2^21977147 is an apocalyptic number.

21977147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21977147 is an equidigital number, since it uses as much as digits as its factorization.

21977147 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24696, while the sum is 38.

The square root of 21977147 is about 4687.9789888608. The cubic root of 21977147 is about 280.1068767167.

The spelling of 21977147 in words is "twenty-one million, nine hundred seventy-seven thousand, one hundred forty-seven".