65621531 has 2 divisors, whose sum is σ = 65621532. Its totient is φ = 65621530.

The previous prime is 65621509. The next prime is 65621533. The reversal of 65621531 is 13512656.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 65621531 - 2¹⁸ = 65359387 is a prime.

It is a super-2 number, since 2×65621531² = 8612370661567922, which contains 22 as substring.

Together with 65621533, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 65621494 and 65621503.

It is not a weakly prime, because it can be changed into another prime (65621533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32810765 + 32810766.

It is an arithmetic number, because the mean of its divisors is an integer number (32810766).

Almost surely, 2^65621531 is an apocalyptic number.

65621531 is a deficient number, since it is larger than the sum of its proper divisors (1).

65621531 is an equidigital number, since it uses as much as digits as its factorization.

65621531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5400, while the sum is 29.

The square root of 65621531 is about 8100.7117588518. The cubic root of 65621531 is about 403.3500540997.

The spelling of 65621531 in words is "sixty-five million, six hundred twenty-one thousand, five hundred thirty-one".