21261774 has 8 divisors (see below), whose sum is σ = 42523560. Its totient is φ = 7087256.

The previous prime is 21261767. The next prime is 21261787. The reversal of 21261774 is 47716212.

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

21261774 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1771809 + ... + 1771820.

It is an arithmetic number, because the mean of its divisors is an integer number (5315445).

Almost surely, 2^21261774 is an apocalyptic number.

21261774 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21261774 is a wasteful number, since it uses less digits than its factorization.

21261774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3543634.

The product of its digits is 4704, while the sum is 30.

The square root of 21261774 is about 4611.0491214039. The cubic root of 21261774 is about 277.0340594211.

Adding to 21261774 its reverse (47716212), we get a palindrome (68977986).

The spelling of 21261774 in words is "twenty-one million, two hundred sixty-one thousand, seven hundred seventy-four".