21801376 has 12 divisors (see below), whose sum is σ = 42921522. Its totient is φ = 10900672.

The previous prime is 21801371. The next prime is 21801383. The reversal of 21801376 is 67310812.

It can be written as a sum of positive squares in only one way, i.e., 21344400 + 456976 = 4620^2 + 676^2 .

It is not an unprimeable number, because it can be changed into a prime (21801371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340615 + ... + 340678.

Almost surely, 2^21801376 is an apocalyptic number.

It is an amenable number.

21801376 is a deficient number, since it is larger than the sum of its proper divisors (21120146).

21801376 is an equidigital number, since it uses as much as digits as its factorization.

21801376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681303 (or 681295 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21801376 is about 4669.1943630567. The cubic root of 21801376 is about 279.3581215040.

It can be divided in two parts, 218013 and 76, that added together give a square (218089 = 467²).

The spelling of 21801376 in words is "twenty-one million, eight hundred one thousand, three hundred seventy-six".