21477739 has 2 divisors, whose sum is σ = 21477740. Its totient is φ = 21477738.

The previous prime is 21477697. The next prime is 21477763. The reversal of 21477739 is 93777412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21477739 - 2⁷ = 21477611 is a prime.

It is a super-2 number, since 2×21477739² = 922586545104242, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21477439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10738869 + 10738870.

It is an arithmetic number, because the mean of its divisors is an integer number (10738870).

Almost surely, 2^21477739 is an apocalyptic number.

21477739 is a deficient number, since it is larger than the sum of its proper divisors (1).

21477739 is an equidigital number, since it uses as much as digits as its factorization.

21477739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 74088, while the sum is 40.

The square root of 21477739 is about 4634.4081607040. The cubic root of 21477739 is about 277.9688861544.

It can be divided in two parts, 2 and 1477739, that added together give a palindrome (1477741).

The spelling of 21477739 in words is "twenty-one million, four hundred seventy-seven thousand, seven hundred thirty-nine".