21389754970 has 16 divisors (see below), whose sum is σ = 38661320808. Its totient is φ = 8520399360.

The previous prime is 21389754949. The next prime is 21389754973. The reversal of 21389754970 is 7945798312.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20736288001 + 653466969 = 144001^2 + 25563^2 .

It is not an unprimeable number, because it can be changed into a prime (21389754973) 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, 4435299 + ... + 4440118.

Almost surely, 2^21389754970 is an apocalyptic number.

21389754970 is a deficient number, since it is larger than the sum of its proper divisors (17271565838).

21389754970 is a wasteful number, since it uses less digits than its factorization.

21389754970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8875665.

The product of its (nonzero) digits is 3810240, while the sum is 55.

The spelling of 21389754970 in words is "twenty-one billion, three hundred eighty-nine million, seven hundred fifty-four thousand, nine hundred seventy".