21951438285 has 16 divisors (see below), whose sum is σ = 40139773056. Its totient is φ = 10034943168.

The previous prime is 21951438281. The next prime is 21951438287. The reversal of 21951438285 is 58283415912.

It is not a de Polignac number, because 21951438285 - 2² = 21951438281 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21951438281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104530554 + ... + 104530763.

It is an arithmetic number, because the mean of its divisors is an integer number (2508735816).

Almost surely, 2^21951438285 is an apocalyptic number.

It is an amenable number.

21951438285 is a deficient number, since it is larger than the sum of its proper divisors (18188334771).

21951438285 is a wasteful number, since it uses less digits than its factorization.

21951438285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209061332.

The product of its digits is 691200, while the sum is 48.

The spelling of 21951438285 in words is "twenty-one billion, nine hundred fifty-one million, four hundred thirty-eight thousand, two hundred eighty-five".