21477697 has 2 divisors, whose sum is σ = 21477698. Its totient is φ = 21477696.

The previous prime is 21477689. The next prime is 21477739. The reversal of 21477697 is 79677412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13771521 + 7706176 = 3711^2 + 2776^2 .

It is a cyclic number.

It is not a de Polignac number, because 21477697 - 2³ = 21477689 is a prime.

It is a super-2 number, since 2×21477697² = 922582936847618, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21477497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10738848 + 10738849.

It is an arithmetic number, because the mean of its divisors is an integer number (10738849).

Almost surely, 2^21477697 is an apocalyptic number.

It is an amenable number.

21477697 is a deficient number, since it is larger than the sum of its proper divisors (1).

21477697 is an equidigital number, since it uses as much as digits as its factorization.

21477697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 148176, while the sum is 43.

The square root of 21477697 is about 4634.4036293789. The cubic root of 21477697 is about 277.9687049636.

The spelling of 21477697 in words is "twenty-one million, four hundred seventy-seven thousand, six hundred ninety-seven".