21562212461 has 4 divisors (see below), whose sum is σ = 22088120124. Its totient is φ = 21036304800.

The previous prime is 21562212449. The next prime is 21562212487. The reversal of 21562212461 is 16421226512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11928789961 + 9633422500 = 109219^2 + 98150^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21562212461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21562212421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 262953770 + ... + 262953851.

It is an arithmetic number, because the mean of its divisors is an integer number (5522030031).

Almost surely, 2^21562212461 is an apocalyptic number.

It is an amenable number.

21562212461 is a deficient number, since it is larger than the sum of its proper divisors (525907663).

21562212461 is an equidigital number, since it uses as much as digits as its factorization.

21562212461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 525907662.

The product of its digits is 11520, while the sum is 32.

Adding to 21562212461 its reverse (16421226512), we get a palindrome (37983438973).

The spelling of 21562212461 in words is "twenty-one billion, five hundred sixty-two million, two hundred twelve thousand, four hundred sixty-one".