21923949 has 16 divisors (see below), whose sum is σ = 30355200. Its totient is φ = 14064960.

The previous prime is 21923947. The next prime is 21923953. The reversal of 21923949 is 94932912.

It is not a de Polignac number, because 21923949 - 2¹ = 21923947 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21923947) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7327 + ... + 9875.

It is an arithmetic number, because the mean of its divisors is an integer number (1897200).

Almost surely, 2^21923949 is an apocalyptic number.

It is an amenable number.

21923949 is a deficient number, since it is larger than the sum of its proper divisors (8431251).

21923949 is a wasteful number, since it uses less digits than its factorization.

21923949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2660.

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

The square root of 21923949 is about 4682.3016775940. The cubic root of 21923949 is about 279.8806847081.

The spelling of 21923949 in words is "twenty-one million, nine hundred twenty-three thousand, nine hundred forty-nine".