213401778 has 32 divisors (see below), whose sum is σ = 442532160. Its totient is φ = 68523840.

The previous prime is 213401723. The next prime is 213401791. The reversal of 213401778 is 877104312.

It is a happy number.

It is a super-2 number, since 2×213401778² = 91080637707122568, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93001 + ... + 95267.

It is an arithmetic number, because the mean of its divisors is an integer number (13829130).

Almost surely, 2^213401778 is an apocalyptic number.

213401778 is an abundant number, since it is smaller than the sum of its proper divisors (229130382).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

213401778 is a wasteful number, since it uses less digits than its factorization.

213401778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2842.

The product of its (nonzero) digits is 9408, while the sum is 33.

The square root of 213401778 is about 14608.2777218945. The cubic root of 213401778 is about 597.5845277611.

The spelling of 213401778 in words is "two hundred thirteen million, four hundred one thousand, seven hundred seventy-eight".