21289958 has 8 divisors (see below), whose sum is σ = 31955880. Its totient is φ = 10638000.

The previous prime is 21289949. The next prime is 21289969. The reversal of 21289958 is 85998212.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2138 + ... + 6866.

It is an arithmetic number, because the mean of its divisors is an integer number (3994485).

Almost surely, 2^21289958 is an apocalyptic number.

21289958 is a deficient number, since it is larger than the sum of its proper divisors (10665922).

21289958 is a wasteful number, since it uses less digits than its factorization.

21289958 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6982.

The product of its digits is 103680, while the sum is 44.

The square root of 21289958 is about 4614.1042467634. The cubic root of 21289958 is about 277.1564148508.

The spelling of 21289958 in words is "twenty-one million, two hundred eighty-nine thousand, nine hundred fifty-eight".