21216042062531 has 2 divisors, whose sum is σ = 21216042062532. Its totient is φ = 21216042062530.

The previous prime is 21216042062503. The next prime is 21216042062587. The reversal of 21216042062531 is 13526024061212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21216042062531 is a prime.

It is a super-2 number, since 2×21216042062531² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21216042062491 and 21216042062500.

It is not a weakly prime, because it can be changed into another prime (21216042022531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608021031265 + 10608021031266.

It is an arithmetic number, because the mean of its divisors is an integer number (10608021031266).

Almost surely, 2^{21216042062531} is an apocalyptic number.

21216042062531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21216042062531 is an equidigital number, since it uses as much as digits as its factorization.

21216042062531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 35.

The spelling of 21216042062531 in words is "twenty-one trillion, two hundred sixteen billion, forty-two million, sixty-two thousand, five hundred thirty-one".