21770812 has 24 divisors (see below), whose sum is σ = 46103904. Its totient is φ = 8781312.

The previous prime is 21770803. The next prime is 21770831. The reversal of 21770812 is 21807712.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

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, 22393 + ... + 23344.

It is an arithmetic number, because the mean of its divisors is an integer number (1920996).

Almost surely, 2^21770812 is an apocalyptic number.

It is an amenable number.

21770812 is an abundant number, since it is smaller than the sum of its proper divisors (24333092).

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

21770812 is a wasteful number, since it uses less digits than its factorization.

21770812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45765 (or 45763 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 21770812 is about 4665.9202736438. The cubic root of 21770812 is about 279.2275136199.

The spelling of 21770812 in words is "twenty-one million, seven hundred seventy thousand, eight hundred twelve".