21903946 has 8 divisors (see below), whose sum is σ = 33476004. Its totient is φ = 10745280.

The previous prime is 21903943. The next prime is 21903983. The reversal of 21903946 is 64930912.

It can be written as a sum of positive squares in 2 ways, for example, as 21022225 + 881721 = 4585^2 + 939^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21903943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103215 + ... + 103426.

Almost surely, 2^21903946 is an apocalyptic number.

21903946 is a deficient number, since it is larger than the sum of its proper divisors (11572058).

21903946 is a wasteful number, since it uses less digits than its factorization.

21903946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206696.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 21903946 is about 4680.1651680256. The cubic root of 21903946 is about 279.7955395115.

It can be divided in two parts, 2190394 and 6, that added together give a square (2190400 = 1480²).

The spelling of 21903946 in words is "twenty-one million, nine hundred three thousand, nine hundred forty-six".