21297477 has 8 divisors (see below), whose sum is σ = 28505664. Its totient is φ = 14143808.

The previous prime is 21297469. The next prime is 21297487. The reversal of 21297477 is 77479212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21297477 - 2³ = 21297469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21297457) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12708 + ... + 14285.

It is an arithmetic number, because the mean of its divisors is an integer number (3563208).

Almost surely, 2^21297477 is an apocalyptic number.

It is an amenable number.

21297477 is a deficient number, since it is larger than the sum of its proper divisors (7208187).

21297477 is a wasteful number, since it uses less digits than its factorization.

21297477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27259.

The product of its digits is 49392, while the sum is 39.

The square root of 21297477 is about 4614.9189592018. The cubic root of 21297477 is about 277.1890388983.

The spelling of 21297477 in words is "twenty-one million, two hundred ninety-seven thousand, four hundred seventy-seven".