21820036946 has 4 divisors (see below), whose sum is σ = 32730055422. Its totient is φ = 10910018472.

The previous prime is 21820036919. The next prime is 21820036993. The reversal of 21820036946 is 64963002812.

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., 18330181321 + 3489855625 = 135389^2 + 59075^2 .

It is a super-2 number, since 2×21820036946² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5455009235 + ... + 5455009238.

Almost surely, 2^21820036946 is an apocalyptic number.

21820036946 is a deficient number, since it is larger than the sum of its proper divisors (10910018476).

21820036946 is a wasteful number, since it uses less digits than its factorization.

21820036946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10910018475.

The product of its (nonzero) digits is 124416, while the sum is 41.

The spelling of 21820036946 in words is "twenty-one billion, eight hundred twenty million, thirty-six thousand, nine hundred forty-six".