21004151537 has 2 divisors, whose sum is σ = 21004151538. Its totient is φ = 21004151536.

The previous prime is 21004151507. The next prime is 21004151543. The reversal of 21004151537 is 73515140012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10600967521 + 10403184016 = 102961^2 + 101996^2 .

It is a cyclic number.

It is not a de Polignac number, because 21004151537 - 2⁸ = 21004151281 is a prime.

It is not a weakly prime, because it can be changed into another prime (21004151507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502075768 + 10502075769.

It is an arithmetic number, because the mean of its divisors is an integer number (10502075769).

Almost surely, 2^21004151537 is an apocalyptic number.

It is an amenable number.

21004151537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004151537 is an equidigital number, since it uses as much as digits as its factorization.

21004151537 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4200, while the sum is 29.

Adding to 21004151537 its reverse (73515140012), we get a palindrome (94519291549).

The spelling of 21004151537 in words is "twenty-one billion, four million, one hundred fifty-one thousand, five hundred thirty-seven".