21050997 has 8 divisors (see below), whose sum is σ = 30619680. Its totient is φ = 12758160.

The previous prime is 21050987. The next prime is 21051011. The reversal of 21050997 is 79905012.

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

It is not a de Polignac number, because 21050997 - 2⁶ = 21050933 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 637909 = 21050997 / (2 + 1 + 0 + 5 + 0 + 9 + 9 + 7).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21050927) 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, 318922 + ... + 318987.

It is an arithmetic number, because the mean of its divisors is an integer number (3827460).

Almost surely, 2^21050997 is an apocalyptic number.

It is an amenable number.

21050997 is a deficient number, since it is larger than the sum of its proper divisors (9568683).

21050997 is a wasteful number, since it uses less digits than its factorization.

21050997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 637923.

The product of its (nonzero) digits is 5670, while the sum is 33.

The square root of 21050997 is about 4588.1365498424. The cubic root of 21050997 is about 276.1155654458.

The spelling of 21050997 in words is "twenty-one million, fifty thousand, nine hundred ninety-seven".