21772842 has 32 divisors (see below), whose sum is σ = 53596032. Its totient is φ = 5742144.

The previous prime is 21772837. The next prime is 21772843. The reversal of 21772842 is 24827712.

It is not an unprimeable number, because it can be changed into a prime (21772843) 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 15 ways as a sum of consecutive naturals, for example, 19393 + ... + 20484.

It is an arithmetic number, because the mean of its divisors is an integer number (1674876).

Almost surely, 2^21772842 is an apocalyptic number.

21772842 is an abundant number, since it is smaller than the sum of its proper divisors (31823190).

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

21772842 is a wasteful number, since it uses less digits than its factorization.

21772842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39902.

The product of its digits is 12544, while the sum is 33.

The square root of 21772842 is about 4666.1378033659. The cubic root of 21772842 is about 279.2361921239.

It can be divided in two parts, 217728 and 42, that multiplied together give a square (9144576 = 3024²).

The spelling of 21772842 in words is "twenty-one million, seven hundred seventy-two thousand, eight hundred forty-two".