21929394 has 16 divisors (see below), whose sum is σ = 45371520. Its totient is φ = 7057680.

The previous prime is 21929393. The next prime is 21929437. The reversal of 21929394 is 49392912.

It is not an unprimeable number, because it can be changed into a prime (21929393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62842 + ... + 63189.

It is an arithmetic number, because the mean of its divisors is an integer number (2835720).

Almost surely, 2^21929394 is an apocalyptic number.

21929394 is an abundant number, since it is smaller than the sum of its proper divisors (23442126).

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

21929394 is a wasteful number, since it uses less digits than its factorization.

21929394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126065.

The product of its digits is 34992, while the sum is 39.

The square root of 21929394 is about 4682.8830863048. The cubic root of 21929394 is about 279.9038530431.

The spelling of 21929394 in words is "twenty-one million, nine hundred twenty-nine thousand, three hundred ninety-four".