21777246 has 24 divisors (see below), whose sum is σ = 47533824. Its totient is φ = 7205280.

The previous prime is 21777241. The next prime is 21777253. The reversal of 21777246 is 64277712.

It is a happy number.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21777246.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21777241) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 1950 + ... + 6881.

It is an arithmetic number, because the mean of its divisors is an integer number (1980576).

Almost surely, 2^21777246 is an apocalyptic number.

21777246 is an abundant number, since it is smaller than the sum of its proper divisors (25756578).

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

21777246 is a wasteful number, since it uses less digits than its factorization.

21777246 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8976 (or 8973 counting only the distinct ones).

The product of its digits is 32928, while the sum is 36.

The square root of 21777246 is about 4666.6096901284. The cubic root of 21777246 is about 279.2550179205.

The spelling of 21777246 in words is "twenty-one million, seven hundred seventy-seven thousand, two hundred forty-six".