21464681 has 8 divisors (see below), whose sum is σ = 25597824. Its totient is φ = 17598240.

The previous prime is 21464671. The next prime is 21464683. The reversal of 21464681 is 18646412.

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 21464681 - 2²² = 17270377 is a prime.

It is a super-2 number, since 2×21464681² = 921465060863522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21464683) 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, 66500 + ... + 66821.

It is an arithmetic number, because the mean of its divisors is an integer number (3199728).

Almost surely, 2^21464681 is an apocalyptic number.

It is an amenable number.

21464681 is a deficient number, since it is larger than the sum of its proper divisors (4133143).

21464681 is a wasteful number, since it uses less digits than its factorization.

21464681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133351.

The product of its digits is 9216, while the sum is 32.

The square root of 21464681 is about 4632.9991366285. Note that the first 3 decimals coincide. The cubic root of 21464681 is about 277.9125417139.

The spelling of 21464681 in words is "twenty-one million, four hundred sixty-four thousand, six hundred eighty-one".