21122761 has 8 divisors (see below), whose sum is σ = 23579424. Its totient is φ = 18755520.

The previous prime is 21122743. The next prime is 21122821. The reversal of 21122761 is 16722112.

It is a happy number.

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 21122761 - 2¹¹ = 21120713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21122161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21856 + ... + 22801.

It is an arithmetic number, because the mean of its divisors is an integer number (2947428).

Almost surely, 2^21122761 is an apocalyptic number.

It is an amenable number.

21122761 is a deficient number, since it is larger than the sum of its proper divisors (2456663).

21122761 is a wasteful number, since it uses less digits than its factorization.

21122761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44711.

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

The square root of 21122761 is about 4595.9505001686. The cubic root of 21122761 is about 276.4289739272.

Adding to 21122761 its reverse (16722112), we get a palindrome (37844873).

The spelling of 21122761 in words is "twenty-one million, one hundred twenty-two thousand, seven hundred sixty-one".