55428991 has 2 divisors, whose sum is σ = 55428992. Its totient is φ = 55428990.

The previous prime is 55428983. The next prime is 55429009. The reversal of 55428991 is 19982455.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55428991 - 2³ = 55428983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55428941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27714495 + 27714496.

It is an arithmetic number, because the mean of its divisors is an integer number (27714496).

Almost surely, 2^55428991 is an apocalyptic number.

55428991 is a deficient number, since it is larger than the sum of its proper divisors (1).

55428991 is an equidigital number, since it uses as much as digits as its factorization.

55428991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129600, while the sum is 43.

The square root of 55428991 is about 7445.0648754729. The cubic root of 55428991 is about 381.2814333664.

The spelling of 55428991 in words is "fifty-five million, four hundred twenty-eight thousand, nine hundred ninety-one".