61881821 has 2 divisors, whose sum is σ = 61881822. Its totient is φ = 61881820.

The previous prime is 61881779. The next prime is 61881863. The reversal of 61881821 is 12818816.

It is a balanced prime because it is at equal distance from previous prime (61881779) and next prime (61881863).

It can be written as a sum of positive squares in only one way, i.e., 34987225 + 26894596 = 5915^2 + 5186^2 .

It is a cyclic number.

It is not a de Polignac number, because 61881821 - 2¹⁴ = 61865437 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61881121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30940910 + 30940911.

It is an arithmetic number, because the mean of its divisors is an integer number (30940911).

Almost surely, 2^61881821 is an apocalyptic number.

It is an amenable number.

61881821 is a deficient number, since it is larger than the sum of its proper divisors (1).

61881821 is an equidigital number, since it uses as much as digits as its factorization.

61881821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6144, while the sum is 35.

The square root of 61881821 is about 7866.4999205492. The cubic root of 61881821 is about 395.5375280778.

The spelling of 61881821 in words is "sixty-one million, eight hundred eighty-one thousand, eight hundred twenty-one".