121821777400 has 48 divisors (see below), whose sum is σ = 283258589040. Its totient is φ = 48724761600.

The previous prime is 121821777377. The next prime is 121821777403. The reversal of 121821777400 is 4777128121.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121821777403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4836840 + ... + 4861960.

It is an arithmetic number, because the mean of its divisors is an integer number (5901220605).

Almost surely, 2^121821777400 is an apocalyptic number.

121821777400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121821777400 is an abundant number, since it is smaller than the sum of its proper divisors (161436811640).

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

121821777400 is a wasteful number, since it uses less digits than its factorization.

121821777400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49384 (or 49375 counting only the distinct ones).

The product of its (nonzero) digits is 43904, while the sum is 40.

The spelling of 121821777400 in words is "one hundred twenty-one billion, eight hundred twenty-one million, seven hundred seventy-seven thousand, four hundred".