21761401 has 4 divisors (see below), whose sum is σ = 21772900. Its totient is φ = 21749904.

The previous prime is 21761393. The next prime is 21761431. The reversal of 21761401 is 10416712.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 3613801 + 18147600 = 1901^2 + 4260^2 .

It is a cyclic number.

It is not a de Polignac number, because 21761401 - 2³ = 21761393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21761431) 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, 2166 + ... + 6943.

It is an arithmetic number, because the mean of its divisors is an integer number (5443225).

Almost surely, 2^21761401 is an apocalyptic number.

It is an amenable number.

21761401 is a deficient number, since it is larger than the sum of its proper divisors (11499).

21761401 is an equidigital number, since it uses as much as digits as its factorization.

21761401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11498.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21761401 is about 4664.9116819078. The cubic root of 21761401 is about 279.1872733681.

The spelling of 21761401 in words is "twenty-one million, seven hundred sixty-one thousand, four hundred one".