21594358658 has 4 divisors (see below), whose sum is σ = 32391537990. Its totient is φ = 10797179328.

The previous prime is 21594358651. The next prime is 21594358673. The reversal of 21594358658 is 85685349512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21025870009 + 568488649 = 145003^2 + 23843^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21594358651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5398589663 + ... + 5398589666.

Almost surely, 2^21594358658 is an apocalyptic number.

21594358658 is a deficient number, since it is larger than the sum of its proper divisors (10797179332).

21594358658 is a wasteful number, since it uses less digits than its factorization.

21594358658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10797179331.

The product of its digits is 10368000, while the sum is 56.

The spelling of 21594358658 in words is "twenty-one billion, five hundred ninety-four million, three hundred fifty-eight thousand, six hundred fifty-eight".