21006600436 has 6 divisors (see below), whose sum is σ = 36761550770. Its totient is φ = 10503300216.

The previous prime is 21006600421. The next prime is 21006600451. The reversal of 21006600436 is 63400660012.

It is an interprime number because it is at equal distance from previous prime (21006600421) and next prime (21006600451).

It can be written as a sum of positive squares in only one way, i.e., 11469124836 + 9537475600 = 107094^2 + 97660^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2625825051 + ... + 2625825058.

Almost surely, 2^21006600436 is an apocalyptic number.

It is an amenable number.

21006600436 is a deficient number, since it is larger than the sum of its proper divisors (15754950334).

21006600436 is a wasteful number, since it uses less digits than its factorization.

21006600436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5251650113 (or 5251650111 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 28.

The spelling of 21006600436 in words is "twenty-one billion, six million, six hundred thousand, four hundred thirty-six".