21400777 has 8 divisors (see below), whose sum is σ = 21669120. Its totient is φ = 21134400.

The previous prime is 21400751. The next prime is 21400781. The reversal of 21400777 is 77700412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21400777 - 2¹⁹ = 20876489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21400747) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 35793 + ... + 36385.

It is an arithmetic number, because the mean of its divisors is an integer number (2708640).

Almost surely, 2^21400777 is an apocalyptic number.

It is an amenable number.

21400777 is a deficient number, since it is larger than the sum of its proper divisors (268343).

21400777 is a wasteful number, since it uses less digits than its factorization.

21400777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 983.

The product of its (nonzero) digits is 2744, while the sum is 28.

The square root of 21400777 is about 4626.0973833243. The cubic root of 21400777 is about 277.6364699529.

The spelling of 21400777 in words is "twenty-one million, four hundred thousand, seven hundred seventy-seven".