21738951 has 48 divisors (see below), whose sum is σ = 36036000. Its totient is φ = 12531456.

The previous prime is 21738949. The next prime is 21738989. The reversal of 21738951 is 15983712.

It is not a de Polignac number, because 21738951 - 2¹ = 21738949 is a prime.

Its product of digits (15120) is a multiple of the sum of its prime factors (240).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738901) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 145825 + ... + 145973.

It is an arithmetic number, because the mean of its divisors is an integer number (750750).

Almost surely, 2^21738951 is an apocalyptic number.

21738951 is a deficient number, since it is larger than the sum of its proper divisors (14297049).

21738951 is a wasteful number, since it uses less digits than its factorization.

21738951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 237 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 21738951 is about 4662.5047989251. The cubic root of 21738951 is about 279.0912331226.

The spelling of 21738951 in words is "twenty-one million, seven hundred thirty-eight thousand, nine hundred fifty-one".