21456477 has 12 divisors (see below), whose sum is σ = 35420320. Its totient is φ = 12260808.

The previous prime is 21456469. The next prime is 21456481. The reversal of 21456477 is 77465412.

21456477 is a `hidden beast` number, since 2 + 1 + 4 + 5 + 647 + 7 = 666.

It is not a de Polignac number, because 21456477 - 2³ = 21456469 is a prime.

It is a super-3 number, since 3×21456477³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456427) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 170227 + ... + 170352.

Almost surely, 2^21456477 is an apocalyptic number.

It is an amenable number.

21456477 is a deficient number, since it is larger than the sum of its proper divisors (13963843).

21456477 is a wasteful number, since it uses less digits than its factorization.

21456477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340592 (or 340589 counting only the distinct ones).

The product of its digits is 47040, while the sum is 36.

The square root of 21456477 is about 4632.1136644085. The cubic root of 21456477 is about 277.8771302856.

The spelling of 21456477 in words is "twenty-one million, four hundred fifty-six thousand, four hundred seventy-seven".