21099974 has 8 divisors (see below), whose sum is σ = 36171408. Its totient is φ = 9042840.

The previous prime is 21099973. The next prime is 21099977. The reversal of 21099974 is 47999012.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21099973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 753557 + ... + 753584.

It is an arithmetic number, because the mean of its divisors is an integer number (4521426).

Almost surely, 2^21099974 is an apocalyptic number.

21099974 is a deficient number, since it is larger than the sum of its proper divisors (15071434).

21099974 is a wasteful number, since it uses less digits than its factorization.

21099974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1507150.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 21099974 is about 4593.4708010392. The cubic root of 21099974 is about 276.3295353251.

The spelling of 21099974 in words is "twenty-one million, ninety-nine thousand, nine hundred seventy-four".