63978091 has 2 divisors, whose sum is σ = 63978092. Its totient is φ = 63978090.

The previous prime is 63978037. The next prime is 63978097. The reversal of 63978091 is 19087936.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-63978091 is a prime.

It is a super-2 number, since 2×63978091² = 8186392256008562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (63978097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31989045 + 31989046.

It is an arithmetic number, because the mean of its divisors is an integer number (31989046).

Almost surely, 2^63978091 is an apocalyptic number.

63978091 is a deficient number, since it is larger than the sum of its proper divisors (1).

63978091 is an equidigital number, since it uses as much as digits as its factorization.

63978091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 63978091 is about 7998.6305702914. The cubic root of 63978091 is about 399.9543510406.

The spelling of 63978091 in words is "sixty-three million, nine hundred seventy-eight thousand, ninety-one".