621616649 has 2 divisors, whose sum is σ = 621616650. Its totient is φ = 621616648.

The previous prime is 621616627. The next prime is 621616663. The reversal of 621616649 is 946616126.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 402724624 + 218892025 = 20068^2 + 14795^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621616649 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (621616609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310808324 + 310808325.

It is an arithmetic number, because the mean of its divisors is an integer number (310808325).

Almost surely, 2^621616649 is an apocalyptic number.

It is an amenable number.

621616649 is a deficient number, since it is larger than the sum of its proper divisors (1).

621616649 is an equidigital number, since it uses as much as digits as its factorization.

621616649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 41.

The square root of 621616649 is about 24932.2411547779. The cubic root of 621616649 is about 853.4423946944.

The spelling of 621616649 in words is "six hundred twenty-one million, six hundred sixteen thousand, six hundred forty-nine".