21150012156557 has 2 divisors, whose sum is σ = 21150012156558. Its totient is φ = 21150012156556.

The previous prime is 21150012156547. The next prime is 21150012156569. The reversal of 21150012156557 is 75565121005112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14203355962756 + 6946656193801 = 3768734^2 + 2635651^2 .

It is a cyclic number.

It is not a de Polignac number, because 21150012156557 - 2¹⁸ = 21150011894413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21150012156547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10575006078278 + 10575006078279.

It is an arithmetic number, because the mean of its divisors is an integer number (10575006078279).

Almost surely, 2^{21150012156557} is an apocalyptic number.

It is an amenable number.

21150012156557 is a deficient number, since it is larger than the sum of its proper divisors (1).

21150012156557 is an equidigital number, since it uses as much as digits as its factorization.

21150012156557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 105000, while the sum is 41.

The spelling of 21150012156557 in words is "twenty-one trillion, one hundred fifty billion, twelve million, one hundred fifty-six thousand, five hundred fifty-seven".