21477641 has 4 divisors (see below), whose sum is σ = 21596484. Its totient is φ = 21358800.

The previous prime is 21477623. The next prime is 21477689. The reversal of 21477641 is 14677412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4080400 + 17397241 = 2020^2 + 4171^2 .

It is a cyclic number.

It is not a de Polignac number, because 21477641 - 2¹⁸ = 21215497 is a prime.

It is a super-2 number, since 2×21477641² = 922578125849762, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21477598 and 21477607.

It is not an unprimeable number, because it can be changed into a prime (21477601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59150 + ... + 59511.

It is an arithmetic number, because the mean of its divisors is an integer number (5399121).

Almost surely, 2^21477641 is an apocalyptic number.

It is an amenable number.

21477641 is a deficient number, since it is larger than the sum of its proper divisors (118843).

21477641 is a wasteful number, since it uses less digits than its factorization.

21477641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118842.

The product of its digits is 9408, while the sum is 32.

The square root of 21477641 is about 4634.3975876051. The cubic root of 21477641 is about 277.9684633756.

The spelling of 21477641 in words is "twenty-one million, four hundred seventy-seven thousand, six hundred forty-one".