61557091 has 2 divisors, whose sum is σ = 61557092. Its totient is φ = 61557090.

The previous prime is 61557061. The next prime is 61557101. The reversal of 61557091 is 19075516.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 61557091 - 2⁵ = 61557059 is a prime.

It is not a weakly prime, because it can be changed into another prime (61557061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30778545 + 30778546.

It is an arithmetic number, because the mean of its divisors is an integer number (30778546).

Almost surely, 2^61557091 is an apocalyptic number.

61557091 is a deficient number, since it is larger than the sum of its proper divisors (1).

61557091 is an equidigital number, since it uses as much as digits as its factorization.

61557091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9450, while the sum is 34.

The square root of 61557091 is about 7845.8327155248. The cubic root of 61557091 is about 394.8444422986.

The spelling of 61557091 in words is "sixty-one million, five hundred fifty-seven thousand, ninety-one".