21073951 has 8 divisors (see below), whose sum is σ = 21364640. Its totient is φ = 20785248.

The previous prime is 21073933. The next prime is 21073967. The reversal of 21073951 is 15937012.

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

It is a cyclic number.

It is not a de Polignac number, because 21073951 - 2⁵ = 21073919 is a prime.

It is a super-2 number, since 2×21073951² = 888222821500802, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21073991) 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, 43030 + ... + 43516.

It is an arithmetic number, because the mean of its divisors is an integer number (2670580).

Almost surely, 2^21073951 is an apocalyptic number.

21073951 is a deficient number, since it is larger than the sum of its proper divisors (290689).

21073951 is a wasteful number, since it uses less digits than its factorization.

21073951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 993.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 21073951 is about 4590.6373195886. The cubic root of 21073951 is about 276.2158877639.

The spelling of 21073951 in words is "twenty-one million, seventy-three thousand, nine hundred fifty-one".