21721123400162 has 16 divisors (see below), whose sum is σ = 35687849807160. Its totient is φ = 9869232538368.

The previous prime is 21721123400147. The next prime is 21721123400177. The reversal of 21721123400162 is 26100432112712.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21721123400147) and next prime (21721123400177).

It can be written as a sum of positive squares in 4 ways, for example, as 21696768364441 + 24355035721 = 4657979^2 + 156061^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11014767473 + ... + 11014769444.

Almost surely, 2^{21721123400162} is an apocalyptic number.

21721123400162 is a deficient number, since it is larger than the sum of its proper divisors (13966726406998).

21721123400162 is a wasteful number, since it uses less digits than its factorization.

21721123400162 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22029536965.

The product of its (nonzero) digits is 8064, while the sum is 32.

Adding to 21721123400162 its reverse (26100432112712), we get a palindrome (47821555512874).

The spelling of 21721123400162 in words is "twenty-one trillion, seven hundred twenty-one billion, one hundred twenty-three million, four hundred thousand, one hundred sixty-two".