55770821 has 2 divisors, whose sum is σ = 55770822. Its totient is φ = 55770820.

The previous prime is 55770817. The next prime is 55770853. The reversal of 55770821 is 12807755.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47761921 + 8008900 = 6911^2 + 2830^2 .

It is a cyclic number.

It is not a de Polignac number, because 55770821 - 2² = 55770817 is a prime.

It is a super-2 number, since 2×55770821² = 6220768950028082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55775821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27885410 + 27885411.

It is an arithmetic number, because the mean of its divisors is an integer number (27885411).

Almost surely, 2^55770821 is an apocalyptic number.

It is an amenable number.

55770821 is a deficient number, since it is larger than the sum of its proper divisors (1).

55770821 is an equidigital number, since it uses as much as digits as its factorization.

55770821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19600, while the sum is 35.

The square root of 55770821 is about 7467.9864086647. The cubic root of 55770821 is about 382.0636138497.

The spelling of 55770821 in words is "fifty-five million, seven hundred seventy thousand, eight hundred twenty-one".